36 THE KINGDOM OF MAN 



populations of unadjusted human beings, animals and 

 plants, which from time to time are ravaged by disease 

 producing uncertainty and dismay in human society. 

 Within the past few years the knowledge of the causes 

 of disease has become so far advanced that it is a mat- 

 ter of practical certainty that, by the unstinted applica- 

 tion of known methods of investigation and consequent 

 controlling action, all epidemic disease could be 

 abolished within a period so short as fifty years. It is 

 merely a question of the employment of the means at 

 our command. Where there is one man of first-rate 

 intelligence employed in detecting the disease-producing 

 parasites, their special conditions of life and the way 

 to bring them to an end, there should be a thousand. 

 It should be as much the purpose of civilized govern- 

 ments to protect their citizens in this respect as it is 

 to provide defence against human aggression. Yet it 

 is the fact that this immensely important control of a 

 great and constant danger and injury to mankind is 

 left to the unorganized inquiries of a few enthusiasts. 

 So little is this matter understood or appreciated, that 

 those who are responsible for the welfare of States, 

 with the rarest exceptions, do not even know that 

 such protection is possible, and others again are so far 

 from an intelligent view as to its importance, that they 

 actually entertain the opinion that it would be a good 

 thing were there more disease in order to get rid of the 

 weakly surplus population ! 



In the spring of 1905 I was enabled to examine in 

 the Pasteur Institute in Paris, the minute spiral thread 

 (see Fig. 6) which has just been discovered and shown to 

 be the cause of the most terrible and widely spread of 

 human diseases, destroying the health and strength of 

 those whom it does not kill and damaging the lives of their 



