90 Report of the Department of Bacteriology of the 



PREVIOUS STUDIES. 



Many workers have contributed to our knowledge of this 

 subject and it will serve the present purpose to indicate merely tin- 

 steps by which this knowledge has progressed. 



In 1877 Lister 2 presented a paper to the Pathological Society at 

 London which contained the following statements : " In this case, 

 the experiment was more rigorously conducted, and here, in the 

 majority of the glasses, at first, sight, you will suppose that no 

 change at all had occurred ; and in two of them I found, at the end 

 of six weeks, that there was no indication whatever of any organ- 

 isms. I topped one of them and found the milk still perfectly 

 fluid, of normal taste and reaction and without any organisms in 

 it ; showing that unboiled milk, as coming from the healthy cow, 

 really has no ferment in it capable of leading to lactic fermenta- 

 tion or any other fermentation, or to any organic development 

 whatever." Thus on the basis mainly of two small samples, only 

 one of which was critically examined, there was founded the 

 theory that the milk within the healthy udder is germ free. This 

 theory was generally held until about 1890. 



Apparently the first quantitative study of bacteria in the udder 

 was made under the direction of Dr. Lehmann. One of his 

 students, Schulz, 3 found that the first milk contained large numbers 

 of bacteria while samples drawn midway and at the close of the 

 milking process contained progressively smaller numbers of germs. 

 The results of this study were also presented by Lehmann (17th 

 Versammlung d. deut. Ver. f. offentl. Gesundheitspflege, Leipsic, 

 Sept. 1891), as the work of Schulz, after they had been published 

 as an Inaugural Dissertation by Schulz in July, 1891. These 

 two presentations have been confused in literature and have been 

 frequently referred to as two separate studies. 



2 Lister, J. Lactic fermentation and its bearing on pathology. Pharrn. 

 Jour, and Trans. (Pathological Society of London) III Series, 8:555-558; 

 572-575. 1878. 



3 Schulz, L. Ueber den Schmutzgehalt der Wurzburger Marktmilch urd 

 die Herkunft der Milchbakterien. Arch. Hyg. 14:260-271. 1892. 



