282 Bulletin 178. 



free except when tlie milk glands are diseased, as with tuberculosis, 

 or with mammitis. In such cases the tubercle bacilli or those 

 causing the inflannnation, are present in the milk when drawn. At 

 other times, it is gerin free as was shown by Pasteur by drawing the 

 milk direct from the udder through a sterile cannula." 



In discussing the sources of contamination of milk, v. Freud- 

 enreich mentions that the first milk drawn always contains bacteria. 

 These he says, liave invaded the teat since the previous milking and 

 are all washed out, so that sterile milk can be obtained toward the 

 latter part of each milking. This explanation of the presence of 

 bacteria in the fore milk is apparently based upon the experiments 

 in which sterile milk has been obtained from the udder. Schultz,* ^ 

 Gernhardt,^ Lehmann,^ Moore,* and Backhaus and C^onheim ^ have 

 worked along this line, merely succeeding in demonstrating that 

 sterile samples may be occasionally obtained from the strippings. 



Moreover v. Freudenreich's results, with the milking tube experi- 

 ment suggested by Pasteur, are diametrically opposed to those of 

 Bolley and Hall.f These writers made a study of the bacteria pres- 

 ent in the milk cistern of the normal udder, drawing their samples 

 by means of a sterilized cannula inserted well into the cistern. 



Bolley questions the accuracy of the dictum : " In the healthy 

 udder, milk is germ free of sterile." He says, " Germs nearly 

 always gain admission to the interior of the teats, and often perhaps, 

 the milk cistern proper where some types may multiply in great 

 numbers." 



* ' Schultz, Archiv. f. Hygiene, XIV (1892) p. 260. 



* Gernhardt, Quant. Spaltpilzunters d. Milcli, Inaug. Dissert, Univ. Jurjew. 

 ^Lehmann, loc. cit. 



•* Moore, Preliminary Investigations Concerning the Number and Nature of Bac- 

 teria in Freshly Drawn Milk. Twelve and Thirteenth Annual Report of the 

 Bureau of Animal Industry, U. S. Dep't of Agr., p. 261. 



'Backhaus and Cronheim, Ber. Landw. Inst. Univ. Kouigsberg, 2 (1897). 

 pp. 12-32. Abstracted in the Experiment Station Record Vol. X, No. 1, 

 p. 87. 



t Bolley and Hall, Uberdie Kontanz von Bacterien Arten in Normaler Erste 

 Roh Milch. Centralblatt f ur Bakteriologie u. Parasitenkunde. II Abt., 1 Band 

 No. 22-23. 



H. L. Bolley, North Dakota Agricultural Experiment Station, Bulletin No. 21, 

 p. 164. 



