and Laboratory Methods. 1187 



respiratory processes of plant tissues which continue for some time in the silage 

 after the silo is packed, thus producing the initial heating ; (2) to the presence of 

 enzymes which are liberated from the plant cells after the death of the plant tissue. 



Micro-organisms, the authors believe, only injure the silage and are of no 

 significance in a properly constructed silo. 



The paper by Behrens deals with the question of the fermentation of tobacco, 

 which has been regarded as due to micro-organisms, but which Loew has some- 

 what recently insisted is the result of enzymes formed in the tobacco leaves. 

 Behrens has tested Loew's conclusion and was able to isolate from the leaves of 

 German tobacco the same chemical products referred to by Loew. After making 

 a somewhat careful study of them and their action, he reaches, however, quite 

 different conclusions from those of Loew. His conclusions are, briefly, that 

 these bodies (oxydase, peroxydase) are formed in tobacco leaves. He is 

 doubtful as to whether they are properly to be called enzymes, and is convinced 

 from his experiments that they cannot be the cause of the tobacco fermentation, 

 inasmuch as they disappear from the leaves before the important fermentation 

 takes place. His experiments further show that these oxydases will not produce 

 ammonia from nicotine, a phenomenon of tobacco fermentation which he 

 attributes to bacteria. He finds, also, that micro-organisms will grow in tobacco 

 when the amount of water is not over 25 per cent., contrary to Loew's claims, 

 and is, therefore, convinced that the chief factor in the proper tobacco fermenta- 

 tion is due to bacteria growth rather than to these chemical bodies produced in 

 the tobacco leaves. H. w. c. 



Harrison. Die Lebensdauer des Tuberkel- Harrison has experimented upon the 

 Bacillus im Kase. Landw. Jahrb. der , , ^ • ■ . • , i i i mi- 



Schweiz. looo. length of time m which tubercle bacilli 



remain alive in cheese. His method of 



experiment has been to inoculate milk with a considerable quantity of tubercle 



culture and then to make the milk into cheese in the ordinary fashion. At 



varying intervals the cheese was tested by inoculation into guinea pigs. These 



animals were studied both clinically and microscopically. He found that, in 



Emmenthaler cheese, the tubercle bacilli were dead at the end of 33-40 days, 



while in Cheddar cheese they might remain alive for 104 days. The conclusion 



is that neither of these cheeses is a source of danger to man, since they are 



seldom eaten until they are four months old, or even older. h. w. c. 



Lameris and Harrevelt. Bakterienbefund in The authors made a study of the 

 Kuhnmilch nach algeheilter Mastitis. Zeit. , . . , .,, 



f. Fl. u. Milch Hyg. 11 : 114,1901. bacteria content of some cows milk 



which had produced cases of diarrhoea. 



Inspection of the source of the milk showed that some of the cows had formerly 



suffered from mastitis, but had apparently recovered. In the milk, however, 



there was present a species of streptococcus which is uniformly found and which 



is really the cause of the intestinal disturbance produced by the use of the milk. 



Inasmuch, however, as the milk produced these disturbances, even after boiling, 



and the streptococci were shown to be killed by this temperature, the authors 



conclude that the trouble arose from the toxines developed in the milk by the 



streptococcus rather than by the direct action of the organisms. h. w. c. 



