1092 EXPERIMENT STATION RECORD. 



The cause of the formation of these odors in the butter is attributed 

 to micro-organisms which produce alcohol from the milk sugar, a cleav- 

 age taking place simultaneously in the glyeerids, which yield acid for 

 the formation of esters. As the glyceric! of butyric acid is the least 

 stable, this is usually principally affected. The freed glycerin under- 

 goes various changes, forming aldehydes and keton-like bodies, accord- 

 ing to Schmid 1 and Mayrhofer. The author coincides with the view of 

 Schmid, that the processes of becoming rancid and of becoming sour 

 are not identical. Rancidity of butter in the stage of development of 

 bouquet is regarded as different from the rancidity of other fats, in 

 which the odor is of less importance, and the fat is rendered unfit for 

 food mainly by the irritating taste. 



Tubercle bacilli in market butter, Obeemuller (Syg. Rundschau, 

 9 (1899), No. 2, pp. 57-79). — In a preliminary communication on this sub- 

 ject 2 it was reported that 14 samples of Berlin butter, tested by injecting 

 5 or G guinea pigs with each sample, were found to be infected with vir- 

 ulent tubercle bacilli. Every animal receiving injections of butter in 

 the abdominal cavity showed signs of tuberculosis, and this was cor- 

 roborated by numerous cultures from the affected parts, which showed 

 tuberculosis in a high degree. 



The present papei* is partly controversial and discusses the earlier 

 investigation in more detail, with a verification of the results on pre- 

 served specimens of affected parts of the animals. It also contains the 

 results of tests, by me.xns of guinea pigs, of 10 additional samples of 

 first-quality butter procured from the same source as in the first inves- 

 tigation. Four samples showed positive evidence of the presence of 

 true tubercle bacilli. Animals injected with other samples were made 

 very sick, and cultures made from the slaughtered animals contained 

 tubercle bacilli in some cases. It was found, in agreement with others, 

 that the action of only slightly pathogenic bacteria was much intensified 

 by the presence of butter fat. For this reason, the treatment of the 

 melted butter in a centrifuge and the use of the sediment for injection 

 is believed to give more reliable results than injection with butter 

 directly. 



The author states in conclusion that a large proportion of the butter 

 samples examined by him contained tubercle bacilli, and the presence 

 of these bacilli in butter in most cities is probably not infrequent. State 

 control of dairy herds is strongly recommended. 



Experiments with calcium chlorid for rendering heated milk 

 suitable for cheese making, Klein and A. Kirsten (Milch Ztg., 27 

 [1898), No. 50, pp. 785-787; 51, pp. 803-805). — This investigation was 

 suggested by the practice of sterilizing milk for butter making and the 

 resulting difficulty of using the skim milk for cheese making. Three 

 series of experiments were made, including a large number of trials in 



1 Ztschr. Analyt. Cheni., 37 (1898), p. 301. 



2 Hyg. Rundschau, 7 (1897), pp. 712-714. 



