DAIRY FARMING DAIRYING. 789 



The authors draw several practical deductions from the results of 

 their work. " Here iu Wisconsin the ordinary curing room almost 

 invariably reaches a temperature in summer incompatible with proper 

 curing," and as the expense of erecting suitable curing and storage 

 rooms is considerable, central cooperative curing stations where the 

 cheese from a number of factories could be shipped for ripening under 

 safe and uniform conditions are suggested. The advantages of such a 

 system are enumerated. 



Further communications on the role of lactic-acid bacteria in 

 the ripening of cheese, E. von Freudenreich (Milch Ztg., 27 (1898), 

 No. 47, p. 738). — The author refers to his previous work on this ques- 

 tion (E. S. E., 10, p. 687), and reports the results of examination of a 

 number of milk cultures of different lactic-acid bacteria more than a 

 year old. These are presented as additional proof of his theory that 

 the formation of soluble proteids during ripening is principally due to 

 lactic-acid bacteria. Mention is made of Campbell's work with pure 

 cultures 1 and a footnote reference is given to Babcock and Russell's 

 discovery of enzyms in milk (p. 785). 



On the question of the decomposition of milk fat in the ripen- 

 ing of cheese, H. Weigmann and A. Backe (Landw. Vers. Stat., 51 

 (1898), No. 1, pp. 1-14; and in Milch Ztg., 27 (1898), No. 48, pp. 757,758; 

 49, pp. 771, 775). — Previous investigations by Weigmann and Henzold 

 showed that in the ripening of cheese the greater portion of the fat was 

 unchanged. According to earlier work by Weigmann the fat iu the 

 ripening of Emmenthaler cheese is either not altered at all or only very 

 slightly. Duclaux, on the other hand, has found that fat undergoes a 

 change during ripening, this change being only slight at first, but very 

 considerable after a long time; and while the change is at first limited 

 to the glycerids of the volatile fatty acids, it is later extended to the 

 glycerid of oleic acid. 



The authors used in their investigations a number of different kinds 

 of cheese of different age, employing the following method of analysis: 

 The cheese was rubbed with sand, extracted with ether, and the dried 

 ether extract purified by taking up in petroleum ether, and again dried 

 at 100 to 105° C. The free fatty acids in the petroleum ether solution 

 were obtained by neutralizing this extract, dissolved in ether and alco- 

 hol, with decinormal soda solution. Any unchanged fat was removed 

 by shaking with petroleum ether. The alcohol was evaporated from the 

 soap and the residue treated with dilute sulphuric acid, and the melted 

 fatty acids removed from the surface, washed with water, and used for 

 further investigation. 



The authors' investigations are believed to show that a decomposition 

 of the fat takes place in the ripening of cheese, though much the 

 larger part of the fat remains unchanged. The cheeses used, where of 

 ordinary ripeness, contained from 1 to 7 per cent of the fat in the form 

 of higher nonvolatile fatty acids. Of the hard cheeses, the newest 



i Jour. Highland and Agr. Soc. Scotland, 5. ser., 10 (1898), pp. 181-224 ; abstract will 

 be given later. 



