422 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1937 



blame on some group of persons who had offended the deity. Then 

 there would be sacrifice and ceremony, solemn processions and pilgrim- 

 ages and the making of vows, all undertaken with the hope of expiating 

 sin and propitiating an angry God. 



The average individual would keep his windows tightly closed at 

 night to keep out the flying demons of disease, and he would certainly 

 wear a protective amulet. If during the epidemic, a savage were to 

 come to our shores with some explorer, he would see nothing new in 

 all this, and could only approve heartily of every detail. 



HOW PROGRESS IS MADE BY THE DESCENDANTS OF THE HERB 



DOCTORS 



But now let us see what the descendants of the herb doctor did 

 when, some 30 years ago, they were asked to send men to India to try 

 to stop the bubonic plague which was raging there as it has done so 

 many times in the past. 



Did the physicians on that commission go into the temples and 

 offer sacrifices to the ludeous goddess of epidemic disease? No, they 

 went to work with microscopes and guinea pigs. First, reckless of 

 their lives, they opened the bodies of people dying with the plague, 

 and studied the characteristic changes in the several organs. Then 

 they put under the microscope a little juice from the enlarged glands 

 in the groin, and always they found millions of tiny germs such as are 

 never found in the tissues of normal persons. Then these germs were 

 cultivated in glass tubes, and a drop of the culture was injected into a 

 guinea pig, and when the animal sickened and died, the autopsy 

 always showed lesions like those of the patients. And so, gradually, 

 it became clear that the cause of the scourge was a living thing, a tiny 

 germ which went into a man and kept multiplying until it killed him. 



The next question was: How did this germ get into the people? 

 Did they drink it or eat it or did it travel through the air? At this 

 point the physicians were helped by a bit of knowledge that had been 

 available for centuries, namely, that always, preceding an epidemic 

 of plague, rats crawl out of their holes and die. Accordingly, hun- 

 dreds of rats from the affected regions were caught and dissected, and 

 in the sickly ones again there appeared the same lesions and the same 

 little germs that had been found in the guinea pigs and in the patients. 

 But how were the germs getting from the rats into the people? Soon 

 the rats' fleas came under suspicion, and when some were removed 

 from a rat dying of the plague and dissected, there again were the 

 germs. 



Then the scientists collected fleas from sick rats and put them on 

 guinea pigs, and the pigs sickened and died of plague. They always 

 got the disease also when they were left in cages on the floors of the 

 huts where men were dying of plague and their fleas were hopping 



