10 MICROBES AND THE MICROBE-KILLER. 



Ill the course of my observations and experiments I 

 have often observed that in times when coughs were 

 prevalent, and when what appeared to be ordinary colds 

 assumed the character of an epidemic, vegetation was 

 also affected Plants did not flourish in their customary 

 manner. The young leaves chiefly suffered ; sometimes 

 evidences of the existence of microbes became visible on 

 the more tender parts, and the whole plant would as- 

 sume a stricken and unhealthy appearance. 



The changes which generally occur in springtime — 

 changes not only in temperature but in the degree of 

 moisture or dryness of the atmosphere — are especially 

 calculated to produce disease in vegetation exactly as 

 they do in man, and the affection is more severe and 

 more diflicult to combat. 



Plants kept in places where they were away from the 

 full exhilarating influence of light, or in an atmosphere 

 where there was no free circulation of air, would speed- 

 ily become sickly, and their growth, if any, would be 

 weak and unhealthy. 



Man, submitted to similar conditions, suffers in the 

 same way, and children brought up in close places, or 

 even being made to work in them, where air and light 

 are insufficiently supplied, become stunted in growth. 

 The tissues of their bodies are weakened, their senses are 

 not fully developed, and their minds are imperfectly 

 formed. Poverty, crime, and much misery are too often 

 the lot of such persons, and all their misfortune may 

 be attributed to the fact of their having been confined in 

 surroundings where disease germs are so abundant that 

 the microbes necessarily obtain access to the blood and 

 are circulated with it through all parts of the system. 



I may here direct attention to two well-known dis- 

 eases, whooping cough (see Plate X., No. 37) and diph- 

 theria (see Plate IX., No. 36), by way of illustrating 

 further some points that I have mentioned. Both of 

 these may result from infection, and one, if not both, 

 may also arise from the use or presence of impure water 

 or decaying vegetation. They are, however, produced 



