76 EXPERIMENT STATION EECOBD. 



mucous membrane; stimulation of the pituitary body by this substance; and 

 increased diuresis, 



DAIRY FARMING— DAIRYING. 



Official tests of dairy cows, F. W. Woll and Coba J. Hiul {California Sta. 

 Circ. 135 (1915), pp. 10, figs. 4)- — This circular gives general instructions on 

 methods of making official dairy tests and the rules governing them. 



Cream and milk {Maine Sta. Off. Insp. 69 {1915), pp. 57-68; 11 {1915), pp. 

 81-100). — The results of examinations of samples of milk and cream in Maine 

 are given. General notes by A. M. G. Soule on conditions in the State are in- 

 cluded (pp. 97-100). 



Dairy bacteriolog'y at the Beme Congress, 1914, C. Gorini {Bol. J/jh. Agr., 

 Indus, e Com. IRome], Ser. B, IJf {1915), I, Xo. 3-4, pp. 80-84; abs. in Cream, 

 and Milk Plant Mo., 3 {1915), No. 10, pp. 24-26). — In a report of this congress 

 the author states that observations made by Alice Evans, E. C. Hastings, and 

 O. Gratz corroborate his conclusion that several groups of lactic acid bacteria 

 are concerned in the ripening of cheese, including among others the round 

 forms of the micrococcus tjTpe, divided into two classes, one which does and one 

 which does not liquefy gelatin {Micrococcus casci acido-protcoUjticus I and II). 

 The necessity of basing the distinction of lactic acid bacteria not so much upon 

 form as upon physico-chemical properties, and of keeping up a distinction be- 

 tween the acido-proteolytic organisms, so called because they are capable of 

 attacking the casein in an acid medium, and the common lactic acid bacteria 

 or alkalino-proteolytic organisms, so called because they can attack the casein 

 only in alkaline or at least neutral media, was emphasized. 



The classification of the lactic acid bacteria, it was maintained, should be 

 based upon prolonged and repeated observations as to changes in the quality 

 of the milk and conditions of life as to temperature, aerobiosis, etc. These 

 observations were confirmed by O. Jensen. It is believed that the variability 

 of the bacterium, other things being equal, depends upon dilTerencos in the 

 quality of the milk. The milk quality is subject to substantial Iluctuations 

 according to types, physiological condition, and feed of cows, etc., modifica- 

 tions of the milk before it reaches the laboratory, sterilization or preser\-ation 

 before inoculation, etc. S. Paraschtschuck called attention to the great differ- 

 ence in resistance, aroma, and fermenting power of different tM>es of lactic 

 acid bacteria according to the varying properties of the milk. In a gocKl, 

 freshly taken milk the lactic bacteria are strong and, as it were, rejuvenated; 

 in a poor, badly kept milk, though sterilized, they become weak because sterili- 

 zation fails to destroy the toxic products present in the milk. This confirms 

 the theory that in order to improve cheese manufacture and profitably use pure 

 cultures it is necessary to start with a hygienic milk. 



The development of peptonizing germs in the culture milk before sterilization 

 may exert a marked influence upon the behavior of the lactic acid bacteria. 

 O. Jensen confirmed this observation and suggested the addition of peptone 

 to milk for the purpose of strengthening these bacteria. The author states 

 that his acid-rennet-forming bacteria act in a similar way, there being a pep- 

 tonizing action upon the casein and a consequent stimulation of the activity of 

 the microbes within the cheese. Also, the acid-renuet-forming bacteria from 

 the udder contribute to the ripening of cheese by generating peptone in the 

 milk. 



O. Jensen called attention to the capacity of young lactic acid bacteria to 

 produce ropiness. This phenomenon has not been fully understood by Investi- 

 gators. Most lactic acid bacteria in the first stages of development form a 



