1032 BACTERIA IN AIR, SOIL, WATER, AND MILK 



has been brought, it has been sufficiently convincing to necessitate 

 the most careful investigation into milk supplies whenever epidemics 

 of certain infectious maladies occur. 



Typhoid-fever epidemics have been frequently traced to milk 

 infection, and, in this disease, milk is, next to water, the most 

 frequent etiological factor. Schiider, 14 in an analysis of six hundred 

 and fifty typhoid epidemics, found four hundred and sixty-two 

 attributed to water, one hundred and ten to milk, and seventy-eight 

 to all other causes. 



Trask 15 compiled statistics of one hundred and seventy-nine 

 typhoid epidemics supposed to have been caused by milk, in various 

 parts of the world. In all such epidemics the origin of infection was 

 generally traceable to diseased or convalescent persons employed in 

 dairies, to contaminated well water used in washing milk utensils, 

 or to the use of cans and bottles returned from dwellings where 

 typhoid fever had existed. Actual bacteriological proof of the in- 

 fectiousness of milk by the isolation of Bacillus typhosus is rare, 

 but has been accomplished in isolated instances. In the case of 

 one epidemic, Conradi 16 isolated the bacillus from the milk on sale 

 at a bakery at which a large number of the infected individuals had 

 purchased their milk. The examination of market milk at Chicago, 

 through a period of eight years, revealed the presence of typhoid 

 bacilli but three times. 



In spite of the few cases in which actual bacteriological proof 

 has been brought, it is not unlikely that careful and systematic 

 researches would reveal a far greater number, since many writers 

 have shown that typhoid bacilli may remain alive in raw milk for 

 as long as thirty days, 17 and may actively proliferate in the milk 

 during this time. One peculiarity of epidemics which may aid in 

 arousing the suspicion that they have originated in milk is that, 

 in such cases, women and children are far more frequently attacked 

 than men. 18 



A feature which adds considerably to the dangers of milk infec- 

 tion is the unfortunate absence of any gross changes, such as coagula- 

 tion, by the growth of typhoid bacilli. 



14 Schuder, Zeit. f. Hyg., xxxviii, 1901. 



Trask, Bull. No. 41, TI. S. Pub. Health and Mar. Hosp. Serv., Wash. 



16 Conradi, Cent, f . Bakt., I, xl, 1905 



17 Heim, Arb. a. d. kais. Gesundheitsamt, v. 



18 Wilckens, Zeit. f. Hyg., xxvii, 1898. 



