184 EXPERIMENT STATION RECORD. 



The nuinber of liquefying liacteriii was largely increased by separation. The results 

 tend to show that this method of i>urilication, so far as l)aeteria are concerned, is 

 ineffectual. 



From 12,000 to 42,000 bacteria i)er minute were deposited in a 12-in. pail during 

 bedding, while only 400 to 2,000 were deposited p^T minute 1 hour after thi.s oper- 

 ation. From 215,000 to 806,000 bacteria per cubic centimeter were found in the wash- 

 ings of cans i)Oorly cleaned, from 15,000 to 93,000 in the washings of cans washed in 

 tepid water and then scalded, and from 800 to 1,800 in the washings of cans washed 

 in tcpiil water and then steamed for 5 minutes. 



Bacteria in normal milk and their relation to the ripening of cheese, 

 E. VON Freudexreich and J. Thoxi {Landiv. Jahrb. Schweiz, 17 {1903), No. 3, pp. 

 234-246; Ann. Agr. Suisse, 4 {1903), No. 4, pp. 215-229; Rev. Gen. Lait, 2 {1903), 

 Nos. 11, pp. 241-W; 12, pp. 271-280).— &t\id\es, were made of the milkof 15 cows to 

 determine the number and species of the bacteria present. The milking was done 

 with the utmost care to prevent contamination, and gelatin plate cultures were made 

 immediately, one droj:) of the milk from each quarter of the udder being used in 

 separate cultures. Whey-agar stab cultures were also made for the purpose of deter- 

 mining the presence or absence of lactic-acid bacteria. 



The experiments were made in INIarch, 1902, and repeated in April. As regards 

 the total number of bacteria great variations were observed with the different cows 

 and with the different quarters of the udder of the same cow. The species consisted 

 practically of micrococci and a nonliquefying Bacterium. Lactic-acid bacteria 

 were invariably absent. The micrococci consisted of both liquefying and nonlique- 

 fying forms, of which the nonliquefying seemed on the whole to predominate. As 

 the nonliquefying micrococci as well as the nonliquefying Bacterium disappear early 

 in cheese, these organisms were not studied. The liquefying micrococci were grouped 

 according to their morphological and cultural characters into 4 types, some of which 

 included several varieties. The different forms are described, as is also a rapidly 

 liquefying Bacterium isolated from cheese. 



Numerous small exi^erimental cheeses were made in order to study the influence 

 of the different liquefying organisms. The milk used for this purpose was oVjtained 

 with great care and contained on an average 104 bacteria per cubic centimeter. Bac- 

 teriological and chemical examinations were made of the cheeses 7 days after making 

 and again at the end of 5 or 6 months. As in earlier experiments, cheeses made 

 without the addition of cultures showed almost no ripening. The best results were 

 obtained by the use of a liquefying micrococcus isolated from Emmenthaler cheese 

 and closely resembling a micrococcus isolated in one or two instances from milk. 

 The results with the micrococcus isolated from milk were favorable as regards the 

 taste of the cheese, and a further study is to be made of this organism. The other 

 organisms isolated from milk rendered the casein soluble to a greater or less extent, 

 but the cheeses inoculated with them did not undergo normal ripening. 



The micrococcus isolated from cheese is believed to be the only one of importance 

 in the ripening of Emmenthaler cheese, and the role here played is that of render- 

 ing the casein soluble, making it more assimilable to the lactic-acid bacteria which 

 later preilominate and which are the principal agents in cheese ripening. 



The presence of bacteria in the cow's udder, E. von Freudenreich {Lundiv. 

 Jahrb. Schweiz, 17 {1903), No. 3, pp. 201-222; Ann. Agr. Suisse, 4 {1903), No. 4, pp. 

 185-206; Rev. Gen. Lait, 2 {1903), Nos. 16, pp. 361-370; 17, pp. 385-394; 18, pp. 409- 

 417). — Following a review of the literature of this subject bacteriological examina- 

 tions of the udders of 15 cows are reported. Gelatin cultures were made, using portions 

 of glandular tissue from each half of the udder, pieces of mucous membrane from 

 each milk cistern, and in some eases milk obtained from the milk ducts or the 

 glandular tissue. The material for inoculation was obtained in most cases imme- 

 diately after the death of the animal and with great care to prevent contamination. 



