246 CIVIC BIOLOGY 



Every case of " cold " or " sore throat " in a cat should be 

 considered diphtheretic or tubercular until proved otherwise. 

 Serious epidemics of diphtheria have been traced to cats, and 

 these have had to be killed or rigidly excluded from homes 

 before spread of the disease could be stopped. Cases of scar- 

 let fever are sometimes traced to cats as passive carriers. 1 

 While dogs may act as mechanical carriers of bacteria, and 

 are responsible for harboring several animal parasites, which 

 we shall have to consider later, they are almost immune from 

 bacterial attack. 



Recent civic advances due to acceptance of contact infection. 

 Public drinking-cups and common towels have vanished as if 

 by magic. Sanitary regulation of dishwashing and bed linen 

 in hotels and restaurants, sanitary protection of drinking- 

 straws and cleansing of glasses in soda fountains, wrapping 

 and boxing of bread, other foods, and candies, to prevent 

 contact in handling, liquid and individual soaps, and many 

 other items of modern improvement are active steps in the 

 direction of rational prevention of contact infections. As 

 with the dairies, when we all realize that intelligence in per- 

 sonnel is of more importance than equipment, we shall see to 

 it that only the healthy and cleanly and those who know are 

 allowed to work in dairies or take care of foods in markets 

 or eating houses. No man who does not know better than 

 to put his bare hand over a milk bottle, or woman who 

 does not know better than to take candy from a tray with 

 her bare fingers, has any right to serve the public. Our mil- 

 lions of preventable infections and our more than 500,000 

 deaths annually are the measure of our need in this direction. 



Resistance, susceptibility, and immunity. Possibly every 

 American chestnut tree on the continent is susceptible - 



i Caroline A. Osborne, M.D., ff The Cat a Neglected Factor in Sanitary 

 Science," Pedagogical Seminary, 1907 ; also "The Cat and the Transmission 

 of Disease," Medical Recorder, Chicago, 1912. 



