DAIRY FARMING DAIRYING AGROTECHNY. 



1075 



ivsiilts obtained from uiipastt'iiri/.i'il milk, eroani, skim milk, biiltermilk. and 

 milk .sera are summarized in the followiuf? table: 



Clicniirdl cinnitoxUion and iirojnrlUs of niUk. xkiin tnilU. rrcant, and buttcrnnU: 



and the sera therefrom. 



The serum from the acetic acid curd contained more fat than when the milk 

 was otherwise coagulated. The acidity of the serum spontaneously coagulatetl 

 at room temperatures was a little lower than that coagulated in an incubator, 

 but llu' sin'citic .gravity W'as about the same in both cases. 



The specific gravity of pasteurized milk serum was also found to be slightly 

 higher than that of the serum of raw- milk, but on allowing it to curdle spon- 

 taneously the serum of the pasteurized milk was the lower. Pasteurizing low- 

 ered the specific gravity of (he serum of cream and of buttei-milk. Tlie specific 

 gravity of i)ure serum from mixed milk is never under 1.02G0. The ash content 

 of serum sitontaneously curdled varies from 0.75 to 0.8 per cent, a smaller per- 

 centage indicating watering. 



The use of the refractometer is also of service in detecting watered milk. The 

 retractive jiower of siKintaneously curdled serum should not l>e less than S 

 divisions on a Wollny refractometer. Ten per cent of water will lower it one 

 degree. When the blue solution (copper-glycerin-potash) of Baier and Neu- 

 mann is added to milk and the power of refraction is under 20 scale divisions 

 the milk has been watered. 



Experiments on the g-ermicidal action of cow's milk. V. G. Heinkmann and 

 T. 11. (Ji.K.XN (Jour. Infect. Disca.srs, ,5 (/.W,S). .Yo. .7. />/). r,3'i-5',t. /i<j. /. chart 

 1). — The autliors studied tlie bactei-ial content of milk and milk serum obtained 

 by jiassing milk through a P.erkefeld filt(>r. Some of their conclusions are .-is 

 follows : 



"Tlie decrease? of bacteria in fresli cow's milk is more decid(>(l if fairly large 

 iiumliers are inoculated than if small numbers only are present. 



"The relative increase of bacteria in milk is more pronounced in milk In-Mted 

 (o 75° r. or 10(t° ('. (ban in r:iw milk or in milk heated to .^)(i° C. 



" .Milk iiioi-ulaled wi(li imre cullures of b;icteria seems lo restrain (o a m:irked 

 degree the muKiplicadon of these l>;ic(eria for several hours at .'{7° C, and for 

 a somewhat longer ]teriod at room temiieraliire, excepdng in the case of Strciito- 



