CONTROL OF INFECTIOUS DISEASES 755 



mucous membrane as when a well person kisses a diphtheritic child; 

 conveyance of particles through the air, sprayed from the mouth, may 

 occur, as when a diphtheritic patient coughs into an attendant's face; 

 or mucous membranes may be applied to skin or vice versa, as in the 

 kissing of a smallpox patient; but in general the discharges are con- 

 veyed somewhat indirectly. The prime route from mucous membrane 

 to mucous membrane is furnished by the hands. An attendant touches 

 the patient's lip or wipes out the mouth or otherwise performs toilet 

 services and receives the discharges upon his ringers. The fingers go 

 then to the attendant's mouth directly, or touch something (the tines 

 of a fork or the bowl of a spoon, etc.) which in turn goes into his mouth; 

 or the attendant may touch the fork or spoon or food of others and thus 

 they become infected. He may milk a cow and so get the discharges 

 into the milk. With the infection in his own mouth he may kiss 

 others and transfer it to them. It is impossible to outline the infinite 

 combinations that may occur, but the principles are here made obvious. 

 When the infective discharges handled are those of the bladder or 

 bowel (as in typhoid fever, cholera, etc.) the same dangers of trans- 

 mission are encountered and unfortunately too often realized. The 

 wholesale discharge of sewage into water supplies is merely a gross 

 example of the same principle of transfer of discharges from human 

 bodies to the human mouth. 



Another factor in the transmission of disease (as distinguished from 

 the transmission of the germ) is the condition of the infectee. The germ 

 is analogous to a seed; the methods of transmission are somewhat 

 analogous to the distribution of seeds in nature; the condition of the 

 infectee is analogous to the character and nutritional condition of the 

 soil which the seed reaches. 



If for any reason the germ will not develop in the soil where it is 

 planted, or, still further, if it grows but fails to produce those poisons 

 through which alone it acts, or finally if, growing and producing its 

 poisons, the soil neutralizes the poisons, no disease results. Science, 

 logic, and the law (each of which regards itself, and rightly so, as merely 

 an apotheosis in its own line of "common sense") unite in the dictum 

 that a disease exists only when the normal functions of the body are in 

 some way interfered with to the detriment of the body. The mere in- 

 fection of the body with a disease germ does not, in science, logic, or 

 the law, constitute disease. Hence, the reception of a disease germ 



