This is a reproduction of a library book that was digitized by Google as part of an ongoing effort to preserve the information in books and make it universally accessible.

https://books.google.com

B 943,752

1817

ARTE S

SCIENTIA

VERITAS

LIBRARY OF THE

UNIVE RSITY

OF MICHI

GAN

TEROR

SLOVARIS -PENINSULAM-AMCENAS

CIRCUMSPICE

1

}

{

1

1

i

1

1

MICROBE HUNTERS

by

PAUL DE KRUIF

“The gods are frankly human, sharing in

the weaknesses of mankind, yet not un

touched with a halo of divine Romance. "

E. H. BLAKEMEY .

brb

BLUE RIBBON BOOKS

NEW YORK

QR

033

2

COPYRIGHT, 1926, BY

FARCOURT, BRACE AND COMPANY, INC .

PRINTED IN THE UNITED STATES OF AMERICA

و اک ر

)

PRINTED BY THE CORNWALL PRESS, INC .

CORNWALL, N. Y.

2

TO

RHEA

1

1

1

Ayhan 't

F. E. RA

FRESHMAN COLLEGES FUND

finalan Sewie

State

31847

* emps:

CONTENTS

CHAPTER PAGT

I LEEUWENHOEK : First of the Microbe Hunters 3

II SPALLANZANI: Microbes Must Have Parents ! . • 25

III PASTEUR : Microbes Are a Menace ! . 57

IV KOCH : The Death Fighter 105

V PASTEUR : And the Mad Dog . 145

VI ROUX AND BEHRING: Massacre the Guinea – Pigs . 184

VII METCHNIKOFF : The Nice Phagocytes 207

VIII THEOBALD SMITH: Ticks and Texas Fever 234.

IX BRUCE : Trail of the Tsetse . 252

. 278X ROSS VS. GRASSI: Malaria .

– XI WALTER REED : In the Interest of Science and for

Humanity ! . . 311

XII PAUL EHRLICH : The Magic Bullet . . 334

INDEX 359

CHAPTER I

LEEUWENHOEK

FIRST OF THE MICROBE HUNTERS

I

Two hundred and fifty years ago an obscure man named

Leeuwenhoek looked for the first time into a mysterious new

world peopled with a thousand different kinds of tiny beings,

some ferocious and deadly, others friendly and useful, many

of them more important to mankind than any continent or

archipelago .

Leeuwenhoek, unsung and scarce remembered, is now almost

as unknown as his strange little animals and plants were at the

time he discovered them . This is the story of Leeuwenhoek,

the first of the microbe hunters. It is the tale of the bold and

persistent and curious explorers and fighters of death who came

after him. It is the plain history of their tireless peerings into

this new fantastic world . They have tried to chart it , these

microbe hunters and death fighters. So trying they have

groped and fumbled and made mistakes and roused vain hopes.

Some of them who were too bold have died – done to death by

the immensely small assassins they were studying — and these

have passed to an obscure small glory.

To – day it is respectable to be a man of science. Those who

go by the name of scientist form an important element of the

population, their laboratories are in every city, their achieve

ments are on the front pages of the newspapers, often before

they are fully achieved . Almost any young university student

can go in for research and by and by become a comfortable

science professor at a tidy little salary in a cozy college. But

4 LEEUWENHOEK

take yourself back to Leeuwenhoek's day, two hundred and

fifty years ago, and imagine yourself just through high school,

getting ready to choose a career, wanting to know

You have lately recovered from an attack of mumps, you

ask your father what is the cause of mumps and he tells you

a mumpish evil spirit has got into you. His theory may not

impress you much , but you decide to make believe you believe

him and not to wonder any more about what is mumps – be

cause if you publicly don't believe him you are in for a beating

and may even be turned out of the house. Your father is

Authority.

That was the world three hundred years ago, when Leeuwen

hoek was born . It had hardly begun to shake itself free from

superstitions, it was barely beginning to blush for its ignorance.

It was a world where science (which only means trying to find

truth by careful observation and clear thinking) was just

learning to toddle on vague and wobbly legs . It was a world

where Servetus was burned to death for daring to cut up and

examine the body of a dead man , where Galileo was shut up for

life for daring to prove that the earth moved around the sun.

Antony Leeuwenhoek was born in 1632 amid the blue wind

mills and low streets and high canals of Delft, in Holland. His

family were burghers of an intensely respectable kind and I

say intensely respectable because they were basket -makers and

brewers, and brewers are respectable and highly honored in

Holland. Leeuwenhoek's father died early and his mother

sent him to school to learn to be a government official, but he

left school at sixteen to be an apprentice in a dry -goods store

in Amsterdam. That was his university. Think of a present

day scientist getting his training for experiment among bolts of

gingham , listening to the tinkle of the bell on the cash drawer,

being polite to an eternal succession of Dutch housewives who

shopped with a penny – pinching dreadful exhaustiveness — but

that was Leeuwenhoek's university, for six years !

At the age of twenty -one he left the dry – goods store, went

back to Delft, married, set up a dry -goods store of his own

FIRST OF THE MICROBE HUNTERS 5

there. For twenty years after that very little is known about

him , except that he had two wives ( in succession ) and several

children most of whom died, but there is no doubt that during

this time he was appointed janitor of the city hall of Delft, and

that he developed a most idiotic love for grinding lenses . He

had heard that if you very carefully ground very little lenses

out of clear glass , you would see things look much bigger than

they appeared to the naked eye. … Little is known about

him from twenty to forty , but there is no doubt that he passed

in those days for an ignorant man. The only language he knew

was Dutch — that was an obscure language despised by the cul

tured world as a tongue of fishermen and shop-keepers and

diggers of ditches. Educated men talked Latin in those days,

but Leeuwenhoek could not so much as read it and his only

literature was the Dutch Bible. Just the same, you will see

that his ignorance was a great help to him, for, cut off from all

of the learned nonsense of his time, he had to trust to his own

eyes , his own thoughts, his own judgment. And that was easy

for him because there never was a more mulish man than this

Antony Leeuwenhoek !

It would be great fun to look through a lens and see things

bigger than your naked eye showed them to you! But buy

lenses ? Not Leeuwenhoek ! There never was a more sus

picious man. Buy lenses ? He would make them himself !

During these twenty years of his obscurity he went to spec

tacle-makers and got the rudiments of lens-grinding. He

visited alchemists and apothecaries and put his nose into their

secret ways of getting metals from ores , he began fumblingly

to learn the craft of the gold- and silversmiths. He was a most

pernickety man and was not satisfied with grinding lenses as

good as those of the best lens-grinder in Holland, they had to

be better than the best, and then he still fussed over them for

long hours. Next he mounted these lenses in little oblongs of

copper or silver or gold, which he had extracted himself, over

hot fires, among strange smells and fumes. To-day searcbers

pay seventy -five dollars for a fine shining microscope, turn the

6 LEEUWENHOEK

)

screws, peer through it, make discoveries — without knowing

anything about how it is built. But Leeuwenhoek

Of course his neighbors thought he was a bit cracked but

Leeuwenhoek went on burning and blistering his hands. Work

ing forgetful of his family and regardless of his friends , he

bent solitary to subtle tasks in still nights. The good neighbors

sniggered, while that man found a way to make a tiny lens , less

than one -eighth of an inch across, so symmetrical, so perfect,

that it showed little things to him with a fantastic clear enor

mousness. Yes, he was a very uncultured man, but he alone

of all men in Holland knew how to make those lenses, and he

said of those neighbors : "We must forgive them , seeing that

they know no better."

Now this self – satisfied dry -goods dealer began to turn his

lenses onto everything he could get hold of . He looked

through them at the muscle fibers of a whale and the scales of

his own skin . He went to the butcher shop and begged or

bought ox -eyes and was amazed at how prettily the crystalline

lens of the eye of the ox is put together. He peered for hours

at the build of the hairs of a sheep, of a beaver, of an elk, that

were transformed from their fineness into great rough logs

under his bit of glass . He delicately dissected the head of a

fly ; he stuck its brain on the fine needle of his microscope

how he admired the clear details of the marvelous big brain of

that fly ! He examined the cross-sections of the wood of a

dozen different trees and squinted at the seeds of plants . He

grunted " Impossible !” when he first spied the outlandish large

perfection of the sting of a flea and the legs of a louse . That

man Leeuwenhoek was like a puppy who sniffs — with a totally

impolite disregard of discrimination — at every object of the

world around him!

!

II

There never was a less sure man than Leeuwenhoek . He

looked at this bee's sting or that louse's leg again and again

FIRST OF THE MICROBE HUNTERS 7

a

and again . He left his specimens sticking on the point of his

strange microscope for months — in order to look at other

things he made more microscopes till he had hundreds of them !

—then he came back to those first specimens to correct his first

mistakes. He never set down a word about anything he peeped

at, he never made a drawing until hundreds of peeps showed

him that, under given conditions, he would always see exactly

the same thing. And then he was not sure ! He said :

“People who look for the first time through a microscope

say now I see this and then I see that — and even a skilled ob

server can be fooled . On these observations I have spent more

time than many will believe, but I have done them with joy,

and I have taken no notice of those who have said why take

so much trouble and what good is it ? —but I do not write for

such people but only for the philosophicall” He worked for

twenty years that way, without an audience.

But at this time, in the middle of the seventeenth century,

great things were astir in the world. Here and there in France

and England and Italy rare men were thumbing their noses at

almost everything that passed for knowledge. “We will no

longer take Aristotle's say – so , nor the Pope's say-so ,” said these

rebels. “We will trust only the perpetually repeated observa

tions of our own eyes and the careful weighings of our scales ;

we will listen to the answers experiments give us and no other

answers!” So in England a few of these revolutionists started

a society called The Invisible College , it had to be invisible be

cause that man Cromwell might have hung them for plotters

and heretics if he had heard of the strange questions they were

trying to settle. What experiments those solemn searchers

made! Put a spider in a circle made of the powder of a uni

corn's horn and that spider can't crawl out — so said the wis

dom of that day. But these Invisible Collegians ? One of

them brought what was supposed to be powdered unicorn's

horn and another came carrying a little spider in a bottle . The

college crowded around under the light of high candles. Si

8 LEEUWENHOEK

lence, then the hushed experiment, and here is their report of

it :

" A circle was made with the powder of unicorn's horn and a

spider set in the middle of it , but it immediately ran out. ”

Crude, you exclaim. Of course ! But remember that one of

the members of this college was Robert Boyle, founder of the

science of chemistry , and another was Isaac Newton. Such

was the Invisible College, and presently, when Charles II came

to the throne , it rose from its depths as a sort of blind-pig

scientific society to the dignity of the name of the Royal So

ciety of England. And they were Antony Leeuwenhoek's first

audience ! There was one man in Delft who did not laugh at

Antony Leeuwenhoek, and that was Regnier de Graaf, whom

the Lords and Gentlemen of the Royal Society had made a cor

responding member because he had written them of interesting

things he had found in the human ovary . Already Leeuwen

hoek was rather surly and suspected everybody, but he let de

Graaf peep through those magic eyes of his, those little lenses

whose equal did not exist in Europe or England or the whole

world for that matter. What de Graaf saw through those

microscopes made him ashamed of his own fame and he hur

ried to write to the Royal Society :

"Get Antony Leeuwenhoek to write you telling of his dis

coveries. "

And Leeuwenhoek answered the request of the Royal So

ciety with all the confidence of an ignorant man who fails to

realize the profound wisdom of the philosophers he addresses.

It was a long letter, it rambled over every subject under the

sun , it was written with a comical artlessness in the conversa

tional Dutch that was the only language he knew . The title of

that letter was : " A Specimen of some Observations made by a

Microscope contrived by Mr. Leeuwenhoek, concerning Mould

upon the Skin , Flesh, etc.; the Sting of a Bee , etc.” The Royal

Society was amazed, the sophisticated and learned gentlemen

were amused — but principally the Royal Society was astounded

by the marvelous things Leeuwenhoek told them he could see

FIRST OF THE MICROBE HUNTERS 9

through his new lenses. The Secretary of the Royal Society

thanked Leeuwenhoek and told him he hoped his first com

munication would be followed by others. It was, by hundreds

of others over a period of fifty years. They were talkative let

ters full of salty remarks about his ignorant neighbors, of ex

posures of charlatans and of skilled explodings of superstitions,

of chatter about his personal health — but sandwiched between

paragraphs and pages of this homely stuff, in almost every let

ter, those Lords and Gentlemen of the Royal Society had the

honor of reading immortal and gloriously accurate descriptions

of the discoveries made by the magic eye of that janitor and

shopkeeper. What discoveries!

When you look back at them , many of the fundamental dis

coveries of science seem so simple, too absurdly simple. How

was it men groped and fumbled for so many thousands of years

without seeing things that lay right under their noses ? So

with microbes. Now all the world has seen them cavorting on

movie screens, many people of little learning have peeped at

them swimming about under lenses of microscopes, the green

est medical student is able to show you the germs of I don't

know how many diseases – what was so hard about seeing

microbes for the first time ?

But let us drop our sneers to remember that when Leeuwen

hoek was born there were no microscopes but only crude hand

lenses that would hardly make a ten-cent piece look as large as

a quarter. Through these — without his incessant grinding of

his own marvelous lenses — that Dutchman might have looked

till he grew old without discovering any creature smaller than a

cheese -mite. You have read that he made better and better

lenses with the fanatical persistence of a lunatic ; that he ex

amined everything, the most intimate things and the most

shocking things, with the silly curiosity of a puppy. Yes, and

all this squinting at bee -stings and mustache hairs and what

not were needful to prepare him for that sudden day when he

looked through his toy of a gold -mounted lens at a fraction of

a small drop of clear rain water to discover

10 LEEUWENHOEK

.

What he saw that day starts this history. Leeuwenhoek was

a maniac observer, and who but such a strange man would have

thought to turn his lens on clear, pure water, just come down

from the sky ? What could there be in water but just – water ?

You can imagine his daughter Maria — she was nineteen and

she took such care of her slightly insane father !—watching him

take a little tube of glass, heat it red-hot in a flame, draw it out

to the thinness of a hair. Maria was devoted to her father

-let any of those stupid neighbors dare to snigger at him !-

but what in the world was he up to now, with that hair – fine

glass pipe?

You can see her watch that absent-minded wide-eyed man

break the tube into little pieces, go out into the garden to bend

over an earthen pot kept there to measure the fall of the rain.

He bends over that pot. He goes back into his study. He

sticks the little glass pipe onto the needle of his micro

scope. …

What can that dear silly father be up to?

He squints through his lens . He mutters guttural words

under his breath . …

Then suddenly the excited voice of Leeuwenhoek : "Come

here! Hurry! There are little animals in this rain water . …

They swim ! They play around ! They are a thousand times

smaller than any creatures we can see with our eyes alone. .

Look ! See what I have discovered ! ”

Leeuwenhoek's day of days had come. Alexander had gone

to India and discovered huge elephants that no Greek had ever

seen before — but those elephants were as commonplace to

Hindus as horses were to Alexander . Cæsar had gone to Eng.

land and come upon savages that opened his eyes with wonder

-but these Britons were as ordinary to each other as Roman

centurions were to Cæsar. Balboa ? What were his proud

feelings as he looked for the first time at the Pacific ? Just the

same that Ocean was as ordinary to a Central American Indian

as the Mediterranean was to Balboa. But Leeuwenhoek ? This

FIRST OF THE MICROBE HUNTERS II

a

janitor of Delft had stolen upon and peeped into a fantastic

sub-visible world of little things, creatures that had lived , had

bred , had battled, had died, completely hidden from and un

known to all men from the beginning of time . Beasts these

were of a kind that ravaged and annihilated whole races of men

ten million times larger than they were themselves. Beings

these were, more terrible than fire-spitting dragons or hydra

headed monsters. They were silent assassins that murdered

babes in warm cradles and kings in sheltered places. It was

this invisible, insignificant, but implacable and sometimes

friendly — world that Leeuwenhoek had looked into for the first

time of all men of all countries .

This was Leeuwenhoek's day of days. .

III

That man was so unashamed of his admirations and his sur

prises at a nature full of startling events and impossible things.

How I wish I could take myself back, could bring you back, to

that innocent time when men were just beginning to disbelieve

in miracles and only starting to find still more miraculous facts.

How marvelous it would be to step into that simple Dutch

man's shoes, to be inside his brain and body, to feel his ex

citement — it is almost nauseal – at his first peep at those ca

vorting "wretched beasties.”

That was what he called them , and, as I have told you, this

Leeuwenhoek was an unsure man . Those animals were too

tremendously small to be true, they were too strange to be

true. So he looked again , till his hands were cramped with

holding his microscope and his eyes full of that smarting water

that comes from too -long looking. But he was right ! Here

they were again , not one kind of little creature, but here was

another, larger than the first, " moving about very nimbly be

cause they were furnished with divers incredibly thin feet.”

Wait! Here is a third kind — and a fourth, so tiny I can't

1 2

LEEUWENHOEK

>

make out his shape. But he is alive! He goes about, dashing

over great distances in this world of his water -drop in the little

tube. What nimble creatures !

“ They stop, they stand still as ' twere upon a point, and then

turn themselves round with that swiftness, as we see a top turn

round, the circumference they make being no bigger than that

of a fine grain of sand. ” So wrote Leeuwenhoek .

For all this seemingly impractical sniffing about, Leeuwen

hoek was a hard -headed man . He hardly ever spun theories,

he was a fiend for measuring things. Only how could you make

a measuring stick for anything so small as these little beasts ?

He wrinkled his low forehead : "How large really is this last

and smallest of the little beasts? ” He poked about in the cob

webbed corners of his memory among the thousand other things

he had studied with you can't imagine what thoroughness; he

made calculations: “ This last kind of animal is a thousand

times smaller than the eye of a large louse!” That was an

accurate man . For we know now that the eye of one full

grown louse is no larger nor smaller than the eyes of ten thou

sand of his brother and sister lice.

But where did these outlandish little inhabitants of the rain

water come from ? Had they come down from the sky ? Had

they crawled invisibly over the side of the pot from the ground ?

Or had they been created out of nothing by a God full of

whims ? Leeuwenhoek believed in God as piously as any Seven

teenth Century Dutchman . He always referred to God as the

Maker of the Great All. He not only believed in God but he

admired him intensely — what a Being to know how to fashion

bees' wings so prettily ! But then Leeuwenhoek was a material

ist too. His good sense told him that life comes from life. His

simple belief told him that God had invented all living things

in six days, and, having set the machinery going, sat back to

reward good observers and punish guessers and bluffers. He

stopped speculating about improbable gentle rains of little

animals from heaven. Certainly God couldn't brew those ani

mals in the rain water pot out of nothing! But wait

1

FIRST OF THE MICROBE HUNTERS 13

Maybe ? Well, there was only one way to find out where they

came from. " I will experiment ! ” he muttered.

He washed out a wine glass very clean, he dried it, he held

it under the spout of his eaves -trough, he took a wee drop in

one of his hair – fine tubes. Under his lens it went. … Yes!

They were there, a few of those beasts, swimming about.

“ They are present even in very fresh rain water !” But then,

that really proved nothing, they might live in the eaves-trough

and be washed down by the water . …

Then he took a big porcelain dish, " glazed blue within ,” he

washed it clean , out into the rain he went with it and put it

on top of a big box so that the falling raindrops would splash

no mud into the dish . The first water he threw out to clean

it still more thoroughly . Then intently he collected the next

bit in one of his slender pipes, into his study he went with

it. …

“ I have proved it ! This water has not a single little creature

in it ! They do not come down from the sky !”

But he kept that water ; hour after hour, day after day he

squinted at it — and on the fourth day he saw those wee beasts

beginning to appear in the water along with bits of dust and

little flecks of thread and lint. That was a man from Missouri!

Imagine a world of men who would submit all of their cock

sure judgments to the ordeal of the common -sense experiments

of a Leeuwenhoek !

Did he write to the Royal Society to tell them of this en

tirely unsuspected world of life he had discovered ? Not yet !

He was a slow man . He turned his lens onto all kinds of

water, water kept in the close air of his study, water in a pot

kept on the high roof of his house, water from the not-too

clean canals of Delft and water from the deep cold well in his

garden . Everywhere he found those beasts. He gaped at

their enormous littleness, he found many thousands of them

did not equal a grain of sand in bigness, he compared them to

a cheese -mite and they were to this filthy little creature as a

bee is to a horse. He was never tired with watching them

14 LEEUWENHOEK

" swim about among one another gently like a swarm of mos

quitoes in the air. …"

Of course this man was a groper. He was a groper and a

stumbler as all men are gropers, devoid of prescience, and

stumblers , finding what they never set out to find. His new

beasties were marvelous but they were not enough for him, he

was always poking into everything, trying to see more closely ,

trying to find reasons. Why is the sharp taste of pepper ?

That was what he asked himself one day, and he guessed :

“There must be little points on the particles of pepper and

these points jab the tongue when you eat pepper.

But are there such little points ?

He fussed with dry pepper. He sneezed. He sweat, but

he couldn't get the grains of pepper small enough to put under

his lens . So, to soften it, he put it to soak for several weeks

in water. Then with fine needles he pried the almost invisible

specks of the pepper apart, and sucked them up in a little drop

of water into one of his hair – fine glass tubes. He looked

Here was something to make even this determined man

scatter -brained. He forgot about possible small sharp points

on the pepper . With the interest of an intent little boy he

watched the antics of "an incredible number of little animals,

of various sorts , which move very prettily , which tumble about

and sidewise, this way and that !”

So it was Leeuwenhoek stumbled on a magnificent way to

grow his new little animals.

And now to write all this to the great men off there in Lon

don ! Artlessly he described his own astonishment to them .

Long page after page in a superbly neat handwriting with little

common words he told them that you could put a million of

these little animals into a coarse grain of sand and that one

drop of his pepper-water, where they grew and multiplied so

well , held more than two -million seven -hundred -thousand of

them. …

This letter was translated into English. It was read before

FIRST OF THE MICROBE HUNTERS 15

the learned skeptics — who no longer believed in the magic

virtues of unicorn's horns — and it bowled the learned body

over ! What!What! The Dutchman said he had discovered beasts

so small that you could put as many of them into one little

drop of water as there were people in his native country ?

Nonsense ! The cheese mite was absolutely and without doubt

the smallest creature God had created.

But a few of the members did not scoff. This Leeuwenhoek

was a confoundedly accurate man : everything he had ever

written to them they had found to be true. … So a letter

went back to the scientific janitor, begging him to write them

in detail the way he had made his microscope, and his method

of observing.

That upset Leeuwenhoek . It didn't matter that these stupid

oafs of Delft laughed at him — but the Royal Society? He

had thought they were philosophers ! Should he write them

details, or should be from now on keep everything he did to

himself ? “ Great God, ” you can imagine him muttering,

" these ways I have of uncovering mysterious things, how I

have worked and sweat to learn to do them , what jeering from

how many fools haven't I endured to perfect my microscopes

and my ways of looking!

But creators must have audiences. He knew that these

doubters of the Royal Society should have sweat just as hard

to disprove the existence of his little animals as he himself had

toiled to discover them