1122 EXPERIMENT STATION RECORD. 



lessened formation of lactic acid in such milk. Raw milk loses its power of reaction 

 by heating, while milk treated with formalin is only slightly changed in this respect. 

 Boiled milk showing no reaction is again rendered active by the addition of formalin. 

 The reducing power of raw milk for alcoholic solutions of methylene blue is sensibly 

 decreased by the addition of formalin. 



The influence of formalin upon the enzyms of milk was much more marked than 

 that of the other aldehydes and aldehyde-like bodies studied, which included acet- 

 aldehyde, propylaldehyde, butylaldehyde, benzaldehyde, furfurol, tetramethyl- 

 diamidobenzophenone, and formic acid. 



Chloroform and thymol showed no influence on the enzym reactions. Toluol 

 intensified the reactions for enzyms in raw milk, but not to the extent of formalin, 

 neither was it as effective as formalin in preserving enzym reactions against the 

 effects of heating. 



The oxydases of gum arabicand milk showed marked differences, the former being 

 more resistant to heat and less sensitive to the effects of lactic acid. 



Data are reported on the changes taking place in milk treated with formalin in the 

 proportion of 1 : 5,000 and kept at room temperatures or in a refrigerator at 8 to 10° 

 C. Control samples curdled on the second or third day, while those preserved with 

 formalin showed at that time no increase in acidity. Somewhat different results 

 were obtained with ordinary milk, milk obtained under aseptic precautions, and 

 pasteurized milk. Formalin was found to exert an elective action in preventing the 

 development of lactic-acid bacteria in comparison with other forms. It is also noted 

 that formalin produces changes of a purely chemical nature in milk. 



To determine if proteids suffer changes by the addition of formalin to milk biolog- 

 ical tests were made with rabbits. The precipitins obtained reacted with preserved 

 and raw milk in the same manner and at the same dilution, failing to show, there- 

 fore, any effect of the formalin. 



The results of the investigations are believed by the author to be of practical 

 importance in hygiene in two respects. Various tests hitherto used for distinguish- 

 ing raw and cooked milk are believed to lose their significance, since formalin can 

 restore the reaction lost by heating. As a common idiosyncrasy against milk has 

 been attributed to the milk enzyms, it is considered possible that formalin may 

 increase this idiosyncrasy, since it increases the activity of the enzyms and may, 

 therefore, in this way influence unfavorably the especially sensitive digestive process 

 in infants. 



A bibliography is appended. 



The milk of tuberculous cows, Mousso (Rev. Soc. Sci. Hyg. Aliment., 1 ( IPO}), 

 No. 7, pp. 817-824, pis. 2). — Of 57 samples of milk from cows reacting to the tuber- 

 culin test but showing no clinical symptoms of tuberculosis, 7 samples showed the 

 presence of tubercle bacilli, as determined by inoculation experiments with guinea 

 pigs. The author, therefore, concludes that the milk of all cows reacting to the 

 tuberculin test should be rejected. 



On the distribution of Bacillus enteritidis of Gaertner in cows' milk, E. 

 Klein (Cmtbl. Bakt. u. Par., 1. Alt., Orig., 38 (1905), No. 4, pp. 892, 393).— Of 39 

 samples of milk coining from different farms 10 samples produced a chronic disease 

 of the spleen in guinea pigs as a result of subcutaneous or intraperitoneal injections. 



From the miliary nodules in the spleen a bacillus was isolated which, in cultural 

 characteristics and in inoculation experiments, behaved in all respects like Bacillus 

 enteritidis. The micro-organisms were believed to be present in the original samples 

 in only very small numbers inasmuch as no fatal results followed inoculation. Pine 

 cultures of the organism, however, caused the death of guinea pigs and mice in 5 

 days. The source of the micro-organism in the milk was not ascertained. It is 

 believed that in summer when such milk has been allowed to stand for some time 

 and used in a raw condition bad results might follow. 



