1034 BACTERIA IN AIR, SOIL, WATER, AND MILK 



ical cause. Whether or not these diarrheal conditions depend en- 

 tirely upon the bacterial contents of milk or, in a large number 

 of cases at least, upon the inability of the child to digest cow 's milk 

 because of chemical conditions, must be left undecided. Park and 

 Holt, in analyzing their extensive data, conclude that milk con- 

 taining "over one million bacteria to the cubic centimeter is cer- 

 tainly harmful to the average infant." 



The significance of the presence of streptococci in milk, as an 

 element of danger, has recently received much attention in the 

 literature. Heinemann, 26 who has made a careful comparison of 

 Streptococcus lacticus (formerly spoken of as Bacillus acidi lactici 

 [Krusel]), with other streptococci, has shown that, essentially, this 

 streptococcus does not differ from streptococci from other sources, 

 and is practically indistinguishable by cultural methods from Strep- 

 tococcus pyo genes. Similar comparisons made by Schottmuller, 27 

 Miiller, 28 and others have led to like results. Since streptococci may 

 be found in milk from perfectly normal cows and are almost regularly 

 associated with lactic-acid fermentation, it is unlikely that these 

 microorganisms hold ordinarily any specific relationship to disease. 



Recently, however, a number of epidemics of sore throat caused 

 by streptococci have been traced to milk upon reasonably reliable 

 evidence. Accounts of such epidemics in Chicago and in Baltimore 

 have been published by Capps and Miller 29 and by Hamburger. 30 



The presence of pus cells and leucocytes in milk, together with 

 streptococci, was also formerly regarded as of great importance. 

 Enumerations of leucocytes in milk were first made by Stokes and 

 Weggefarth. 31 Their method of enumeration consisted in centri- 

 fugalizing a definite volume of milk, spreading the entire sediment 

 over a definite area on a slide, and counting the leucocytes found 

 in a number of fields. Calculations from this may then be made 

 as to the number of leucocytes per cubic centimeter. This method, 

 and modifications of it, have been used by a large number of 

 observers, but the value of the conclusions drawn from them has 

 been much exaggerated. Normal milk may contain leucocytes in 



26 Heinemann, Jour. Inf. Dis., 3, 1906. 

 "Schottmuller, Munch, med. Woch., 1903. 



28 Miiller, Arch, f . Hyg., Ivi, 1906. 



29 Capps and Miller, Jour. A. M. A., June, 1912, p. 1848. 



30 Hamburger, Bull, of the Johns Hopk. Hosp., xxiv, Jan., 1913. 

 n Stokes and Weggefarth, Med, News, 91, 1897. 



