38 Proceedings op Indiana Academy of Science 



In the latter fifties, Ignatius Semmelweiss, a physician of Vienna, 

 insisted upon using chlorinated lime for washing the hands and instru- 

 ments previous to all examinations made in the maternity hospital. As 

 a result deaths from puerperal infection fell from as high as 50 per 

 cent to practically nothing. But he was ahead of his time, was perse- 

 cuted and died insane. Twenty years later a monument was erected 

 to him by the International Congress of Hygiene. 



Years later, in 1867, Lord Joseph Lister, aided by Pasteur's work 

 on fermentation, attempted to prevent infection by removing or actually 

 destroying the causative organism by means of germicides. We are all 

 familiar with the benefits accorded mankind through the practice of 

 Listerism or antiseptic surgery. 



Methods of Infection. 



The prevention of infectious diseases as they may occur in sporadic, 

 endemic, epidemic and even pandemic form may be greatly facilitated 

 by taking into account how these organisms enter and later leave the 

 infected animal. How they may be disseminated from individual to 

 individual and how they are perpetuated in nature are also conditions 

 well worth recognizing and of great practical significance. 



I. It was formerly thought that germs could not penetrate into 

 the interior of the body through the unbroken healthy skin or mucous 

 membrane. But nowadays we can say with certainty that they can. 



It was early found that pus organisms could be rubbed into the 

 skin and cause boils. 



Loos, 1902, in Egypt, showed that the hook worm is excreted in 

 the feces, that the larvae are formed in the wet soil and that these 

 larval forms could penetrate the whole skin and go to the intestine. If 

 these relatively large organisms can do this, certainly the smaller, micro- 

 organisms can do likewise. 



With protozoal diseases we have a very clean-cut story. In Dourine 

 (mal du coit; horse syphilis), a tiypanosomal infection {Trypanosoma 

 eqidperdiim) and also in syphilis in man (Treponema pallidum), the 

 mucous surfaces are penetrated and probably it is not necessary to 

 have a lesion. 



Novy demonstrated that if the spirochaetes of the relapsing fevers 

 come in contact with the mucous membrane of the eye 100 per cent 

 infection ensues. 



The application of the non-motile plague germ to the mucosa of 

 the pharynx is more certain to infect than when injected into the 

 body under the skin. 



Fraenkel induced disease by causing the bacillus of tuberculosis 

 to pass through the normal skin. 



Probably all motile and non-motile micro-organisms can penetrate 

 the uninjured mucous membrane and perhaps the skin. 



II. Infection through the Alimentary Canal. This is closely asso- 

 ciated with the previously mentioned avenue of infection. It may occur 

 (a) through contaminated eating utensils; (b) through food contami- 

 nated in handling; by growth; by insects such as flies; and (c) by 

 infections through water and milk. 



