222 



POPULAR SCIENCE MONTHLY. 



than one hundred per cent., on account, 

 perhaps, of the oxygen molecules being 



unbridled. 



TEE WISCONSIN AGRICULTURAL 

 EXPERIMENT STATION. 



The seventh annual report of the 

 Wisconsin Agricultural Experiment Sta- 

 tion is a notable example of a class of 

 literature which is rapidly increasing 

 in extent and in popular interest. The 

 reports of this station have become 

 widely known for the important con- 

 tributions which they contain and for 

 their interest to those who follow the 

 progress of science, as well as to the 

 progressive farmer, whose needs are 

 kept constantly in view. The last re- 

 port, which is for the year ending June 

 30, 1900, is fully up to the standard 

 of previous reports. It adds another 

 chapter to the interesting studies on 

 the process of cheese ripening or curing 

 which Dr. Babcock and Dr. Russell have 

 been conducting for a number of years. 

 In the past their studies have led to the 

 discovery of a natural enzym in milk 

 which has been shown to be an active 

 agent in the digestion of the proteids 

 of cheese, rendering them soluble and 

 digestible. This discovery, which was 

 contrary to the prevalent bacterial the- 

 ory and was opposed by many bacte- 

 riologists, has stood the test, and the 

 theory is now generally believed in, the 

 main point at issue being the extent 

 and the exact character of the changes 

 which the ferment induces. The pres- 

 ent report takes up the action of an- 

 other ferment in cheese, namely, rennet^ 

 which is added during the process of 

 manufacture. There has been much di- 

 versity of opinion as to whether the 

 rennet had any part in the ripening 

 process, but very little real investiga- 

 tion. The most recent writings on the 

 subject have disclaimed any action due 

 to rennet. Babcock and Russell now 

 show that rennet undoubtedly assists 

 in peptonizing the casein of cheese, the 

 active agent being the peptic enzj^ms 

 contained in tlie rennet extracts. The 

 investigation is a quite comprehensive 



one, involving a study of the action 

 of pure pepsin as compared with rennet, 

 the conditions of the acidity most fa- 

 vorable to the action, and the nature of 

 the products. The matter is of consid- 

 erable importance, since it is found that 

 the amount of rennet used influences 

 the rapidity and the thoroughness of 

 the ripening process. The wonder is 

 that a point upon which there has been 

 such marked discrepancy of opinion has 

 not been given a thorough investigation 

 before this. 



Of equal interest is the investiga- 

 tion of the cause and character of the 

 changes in green fodder when preserved 

 as silage in the silo, also by Drs. Bab- 

 cock and Russell. The generally ac- 

 cepted theory of silage formation as fer- 

 mentation changes, due to the action of 

 bacteria and molds, is found to be er- 

 roneous, inasumuch as good silage was 

 made under conditions which positively 

 precluded bacterial activity, i. e., in the 

 presence of anaesthetics. With the aid 

 of an ingeniously-devised closed-circuit 

 respiration apparatus, the authors were 

 able to study the gaseous products and 

 to maintain the conditions entirely un- 

 der their control. The unavoidable 

 losses in ensiling green fodder were 

 found to be due to the formation of 

 water, carbon dioxid and volatile or- 

 ganic acids, which are produced, not as 

 a result of the bacterial action, but as 

 a result of the intromolecular respira- 

 tory processes of the plant tissues. The 

 avoidable losses, on the other hand, are 

 found to be due mainly to the decom- 

 position of organic matter induced by 

 the development of bacteria and molds, 

 whose growth is greatly facilitated -by 

 the admission of air, as a result of im- 

 proper construction of the silo. The 

 bacteria are, therefore, instead of being 

 essential to good silage, only delete- 

 rious. In view of the extent to which 

 silage is now prepared in this country, 

 and the fact that the spoiled or partly 

 spoiled silage is not only a loss but is 

 lilvoly to be injurious to stock, these 

 ; results, which furnish a clearer under- 



