MISCHIEF-MAKERS IN MILK. 213 



nary fermentation of milk is traced to the growth of a micro- 

 organism known as Bacterium lactis, which converts the milk- 

 sugar into lactic acid. The work of decomposition is then taken 

 up by another bacillus, named subtilis, through which butyric acid 

 is produced. Recent experiments made in the cultivation of milk 

 bacteria by Baginski * indicate that the Bacterium lactis is incor- 

 rectly named, and, being responsible for an acetic-acid formation, 

 is better termed aceti. 



There is also a peculiar f ermentator, Bacterium coli, that refuses 

 to meddle with milk-sugar alone, but upon the addition of white 

 of egg shows extraordinary activity, furnishing lactic, formic, and 

 acetic acid. These three — Bacterium aceti, Bacillus subtilis, and 

 Bacterium coli — are the normal visitants f of milk, and the changes 

 dependent upon their presence are well understood. The micro- 

 organisms that breed disease and death appear under exceptional 

 circumstances, against which, so far as they are known, we may 

 carefully guard. 



The bacilli of phthisis, typhoid, and scarlet fever have been 

 detected in milk supposed to be wholesome. Thorough inspection 

 of cattle and dairies may reduce the frequency of infection ; but, 

 until such supervision is the rule, all danger can be avoided by 

 boiling the milk. In the late Congress at Paris on the study of 

 tuberculosis, Dr. Nocard advised this to be done in every case 

 where there existed any tendency to consumption. 



A peculiar sickness,;]; which in its malignant form is similar to 

 anthrax, has been traced to a germ occurring in milk. The con- 

 ditions required for its development are known, and have been 

 artificially produced by feeding cattle with fodder exposed to the 

 dew-fall. The poison is found in sweet milk, butter, cream, and 

 cheese, but not in buttermilk. It is either formed in small quan- 

 tity, or has the property attributed to it of self -attraction. Neither 

 the ptomaine nor the bacillus producing it has been determined, 

 and they offer a new field for experiment. 



The chief mischief-maker is yet unknown, unless it may pos- 

 sibly be identical with the micrococcus * found by Dr. Sternberg 

 in cheese. Its ptomaine, || however, was isolated by Prof. Vaughan, 

 of the University of Michigan, in 1885, and was called, from the 

 substance in which it was discovered, tyrotoxicon — cheese-poison. 



The history of this discovery is interesting. Three hundred 

 cases of cheese-poisoning were recorded in Michigan by the Board 



* " Report of the Physiological Society of Berlin," January 18, 1889. 



f Twenty-three varieties of bacteria were found in intestines of milk-fed infants suffer- 

 ing with summer complaints (Dr. Booker, Baltimore). 

 \ "Science," New York, 1886, vol. viii, p. 482. 



* " Report of the Board of Health of Michigan," 1884-'85, vol. xiii, p. 218. 

 || " Ptomaines and Leucomaines," Vaughan and Novy, p. 56. 



