414 



THE POPULAR SCIENCE MONTHLY. 



which they are subject. This volume is in- 

 tended to substitute knowledge for specula- 

 tion, and to give the dairyman data whereby 

 he can best utilize his products. 



There is a preliminary introduction on 

 bacteria and their relation to dairying, so 

 plainly written that all may comprehend it. 

 With this information as a basis, the author 

 proceeds to consider milk as it is drawn from 

 the udder properly sterile and describes 

 the sources of infection in the stable and 

 their prevention. He calls attention to the 

 danger of pouring abnormal milk on the 

 stable floor or of feeding it to swine. Both 

 in Germany and Denmark swine fed on cen- 

 trifuge milk slime have been found tubercu- 

 lous. 



The author states that milk from tuber- 

 culous cows should not be used without 

 being freed from its infectious qualities. 

 This is unfortunate, for there is no certain 

 and safe method of disinfecting such milk, 

 and Prudden's experiments have shown that 

 the sterilized products of tubercle bacilli 

 will produce organic lesions that are severe 

 and permanent. Such milk should never be 

 used for any purpose, and the cow should be 

 killed. 



We are glad to note the author's empha- 

 sis on better lighting of cow-stables; he 

 might have cited the fact that bright light 

 is inimical to the best growth of micro- 

 organisms. Hesse's experiments, here cited, 

 that in the air of a cow- stable there were 

 one hundred and twenty bacteria and molds 

 while in that of an occupied schoolroom 

 there were only eighty micro-organisms to 

 the litre, only evidences the bad ventilation 

 of each of those places. 



In the section on cooling milk he refers 

 to the value of ice to the dairyman, though 

 it is in a subsequent chapter that he calls 

 attention to the fact that the ice should not 

 come in contact with the milk, because ice 

 may contain pathogenic micro-organisms. 



It would seem that the objection to the 

 use of soda in cleansing milk-vessels is not 

 well founded. In surgical and other disin- 

 fection alkaline water is of value in securing 

 an aseptic condition, and its employment in 

 the cleaning of these vessels seems to us par- 

 ticularly appropriate, though, of course, the 

 vessel should be subsequently scalded with 

 boiling water. A thorough steaming of these 



vessels is one of the best procedures that 

 can be employed. 



The annual cleaning of the stable is a 

 hygienic necessity, and the means of disin- 

 fection herein indicated are easily applied. 



The difference in the number of bacteria 

 in one cubic centimetre of milk that has 

 been obtained in a pasture and in a barn is 

 striking : 



Knopf has found from 60,000 to 100,000 

 bacteria in one cubic centimetre of recently 

 drawn milk, and the author found in milk 

 from a filthy stable from 670,000 to 780,000 

 bacteria per cubic centimetre. The investi- 

 gations made by Sedgwick and Batchelder 

 in Boston showed that milk sold in that city 

 contained from 1,438,000 to 4,577,000 bac- 

 teria per cubic centimetre. The author 

 gives a useful review of the various micro- 

 organisms found in milk, and calls attention 

 to the fact that the kinds are more important 

 than the number of organisms. 



Due importance is attached to the clean- 

 liness of employees in butter and cheese fac- 

 tories, to their clothing and the cleanness of 

 their hands. 



The chapter on milk for city consumption 

 is well written, but State dairy inspectors 

 will have to be much further removed from 

 political influences than they are at present 

 before milk supplied to cities will cease to 

 be a fertile source of causation of tubercu- 

 losis. 



There is no doubt that properly condensed 

 unsweetened milk is one of the best articles 

 that can be used as a milk foodstuff, because 

 it may be diluted with water as necessary, 

 and it does not contain the pus and blood 

 corpuscles, hair, and manure particles that 

 are in any milk sterilized by heating. Fil- 

 tration sterilization has not proved practical. 

 A chapter is devoted to milk pasteurization, 

 which the researches of Freeman and others 

 have shown to be so much more satisfactory 

 than sterilization by heating. 



The advantages of the centrifugal method 

 for cream separation and pasteurir.ation of 

 cream receive due consideration. 



The manufacture and handling of butter 



