DAIRY FARMING — DAIRYING — AGROTECHNY. 777 



by Van Slyke and Van Slyke, from their investigations on the action of dilute 

 acids upon casein (E. S. R., 10, p. 173), that the talking up of acid from the 

 watery solution by casein is a process of " adsorption " is, according to the 

 author, unwarranted. In his opinion " in the absence of any specific criteria 

 and in the absence of any exhaustive exclusion of other and not less probable 

 physical and chemical possibilities, it may be questioned whether 'adsorption' 

 (or ' nieclianical affinity') has yet been proved to exist at all." 



The effects of various salts on the coag'ulation of milk by the ferments 

 of vegetable rennets, C. Gerber and Mile. S, Ledeht (Compt. Rend. Acad. 

 Sci. iraris\, IJ,.-) {1007), Ao.v. 1',, pit. 577-580; 17, pp. 689-6!)2 ; 20, pp. 83J- 

 833). — The authors studied the effect of sodium chlorid on the coagulation of 

 raw and boiled milk by the juice of the paper mulberry {Broussonetia papyri- 

 fera) and that of the fig {Ficus carica). They found that the salt in small 

 quantities accelerates the coagulation of the milk, and even causes this phe- 

 nomenon when the quantity of rennet is too small to act alone. In larger 

 quantity it retards the ct)agulation of raw milk. It acts towards vegetable 

 rennets as salts of calcium towards animal rennet. 



Gei'bei", continuing the investigation, found that the effect of various other 

 alkali salts is the same as that of sodium chlorid. Sodium fluorid has an 

 accelerating action that is somewhat obscured by the delay in the coagulation 

 of the milk, due to precipitation of the calcium. A method for studying the 

 accelerating power of neutral salts of sodium and potassium is outlined. 



The effects of neutral salts of sodium and potassium on the coagulation 

 of cow's milk by vegetable and animal rennets, C. CiERUEK {(Unnpt. Rend. 

 Sor. Biol. [Paris], G3 (1007), Nos. 36, pp. 6J,0-6-'t.', ; 38, pp. 7 38-7. 'lO).— The au- 

 thor found that these salts show no exception to the rule observed in previous 

 studies with other salts (see preceding abstract), that a small quantity acceler- 

 ates and a large quantity retards the coagulating action of vegetable rennet 

 upon cow'^ milk. In the case of animal rennets these salts were found to 

 retard coagulation whatever the quantity added, the retarding action being 

 more pronounced as the quantity of salt was increased. 



Recent investigations on the soluble ferments of milk, A. J. J. Vandevelde 

 (Nounlle.s RccIk relics siir Ics Ferments Holubles da Liiit. Brussels, 1907, pp. 

 85+17/7). — The investigations conducted by the author are described, and tlie 

 results obtained are discussed together with those of other investigators. The 

 studies reported were concerned with lactoi)roteolase, lactolipase, salol enzym, 

 and lactochymosine. 



According to the author's conclusions, cow's milk does not show the prop- 

 erties of lipase, and possesses in a very feeble degree the faculty of decom- 

 posing salol. (Ml the contrary, lactoproteolase and lactochymosine have an 

 actual existence, either as enzym substance or as enzym property. The enzy- 

 matic energy seems independent of such conditions as the age of the cow, the 

 quantity of milk produced, or the stage of lactation, except that colostrum 

 in the early stages is very fee!)ly proteolytic. The energy seems dei)endent only 

 upon special propei'ties of the blood, and varies from one individual to another. 



Contribution to our knowledge of the action of rennin, A. H. Moseley and 

 H. G. Chapman ( I'roe. Linn. Hoe. N. S. Wales, 31 (J90G), pts. 3, p. 568; /,, pp. 

 .'>6.9-.'J7S ) . — It was observed that when sodium or potassi(nn hydroxid was 

 added to milk to neutral iz<' the acidity, clotting by rennin was prevented even 

 when the milk was not completely neutralized. From experiments made to 

 ascertain the cause, the authors conclude that the presence of small quantities 

 of alkali lead to the destruction of the rennin through liberation of free 

 hydroxyl ions. 



