ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 375 



Tubercle Bacilli in Butter. — Dr. 0. Korn * found tubercle bacilli 

 in four out of seventeen samples of market butter. Tbe observations 

 were verified by cultures and experiments on animals. Only once were 

 bacilli resembling tubercle bacilli found. The chief interest in this series 

 of observations on butter lies in the fact that all the samples came from 

 the plains, and thus corroborates an observation of Petri, who called 

 attention to the absence of tubercle bacilli in butter from mountainous 

 districts. 



The experiments of Herren Hormann and Morgenrot f relative to 

 the presence of tubercle bacilli in butter, confirmed the suspicion that 

 pure sterile butter, when injected into the peritoneal sac, was by no means 

 harmless, as peritonitis was found in six out of eight cases. Hence it 

 followed that suspensions of bacteria in butter, even though of low patho- 

 genic power, would produce more marked changes than suspensions 

 of the same bacteria in water. Experiment proved the inference to be 

 correct. The authors report on finding tubercle bacilli in one out of 

 three samples of butter. In this case the presence of tuberculous changes 

 in the viscera was noted, and the disease was transferred to other animals 

 by inoculating them with pieces of the tuberculous organs. 



The authors also examined Camembert cheese, and found in three 

 samples typical tubercle bacilli. The fact that tubercle bacilli can 

 retain their vitality in whey-cheese for a long time is, however, by no 

 means new. 



Bacillus viscosus bruxellensis and Double-faced Beer.J — Prof. H. 

 van Laer's researches on double-faced beer form an important contri- 

 bution to the knowledge of viscous fermentations. Beer is said to be 

 double-faced when it is clear by transmitted light, but appears turbid 

 and fluorescent when inspected by reflected light. The condition appears 

 to be well known in Brussels, where the beers called Iambic, faro, and 

 mars not unfrequently become double-faced. The Iambics are most 

 prone to be affected. The germs arc introduced along with the wort 

 into the fermentation vats, and if subjected to certain conditions all 

 their contents would undergo the change. When infected the beer 

 becomes ropy, viscid, and double-faced. The ropiness passes off in 

 course of time, but the optical phenomenon remains. From the infected 

 fluid was isolated a rodlet, varying in length from l*7-2*8 jx, and in 

 breadth from O'S-O^S/x.. In media which do not become viscous, or 

 from which the viscosity has disappeared, the microbe is provided with 

 a capsule, while in those which are ropy the capsules are united by a 

 glairy zoogloeiform substance. The bacillus was cultivated with success 

 on gelatin-wort plates, on gelatin-broth, yeast-water, milk, and beer-wort. 



Beer-wort when inoculated with a pure culture rapidly became 

 ropy. At first the degree of viscosity increased, but afterwards de- 

 creased, so that by the sixth or seventh day it had returned to the initial 

 degree. The degree of ropiness was found to depend on the composition 

 of the wort. Comparative analyses of healthy and double-faced beers 

 of the same brewings showed that in the latter the extractives are in- 



* Arokiv f. Hygiene, xxxvi. (1899). See Beihefte z. Bot. Centralbl., ix. (1900) 

 p. 144. 



t Hygienische Rundschau. 18'.'8, No. 22. See Beihefte z. Bot, Centralbl., ix. 

 <1900), pp. 145-6. X Ann. Inst. Pasteur, xiv. (1900) pp. 82-101. 



