124 Report of the Department of Bacteriology of the 



that the ratio of variation between the counts obtained by the 

 smeared sediment and the direct methods varied from 1 : 2 to 

 1 : 41. Later Breed 26 showed that the precipitation of the cells 

 in centrifuges and separators depended on the speed of revolution 

 and that in gravity-raised cream practically all of the cells rise with 

 the cream. Other uncontrollable factors make it impossible to 

 obtain any constant proportion of the cells in centrifuge sediments. 

 Later studies of whole milk smears by Breed and Stidger 27 showed 

 that only the general conclusions which had been obtained by the use 

 of the methods of counting where the cells had been counted in the 

 sediments obtained by centrifuging were of value. By the use of 

 the new technique it was demonstrated that many more cells were 

 present in normal milk than had previously been thought to occur. 

 Moreover it was shown that the previous work which had claimed 

 to demonstrate that a relationship exists between the discharge of 

 large numbers of these cells and streptococci was inconclusive. 

 The real reason or reasons for the discharge of the cells was not dis- 

 covered. 



English sanitarians have also been interested in the problems 

 which have arisen concerning the number and significance of these 

 cells. The first paper found which refers to them is one by Eastes 28 

 in which he discusses their sanitary significance. In 1906, Savage 29 

 devised a method of counting the cells which was practically identical 

 with the one devised independently by Doane and Buckley 30 already 

 referred to. His method has been somewhat modified by Hewlett, 

 Villar and Revis 31 who have made extensive studies concerning 

 the number and nature of the cells in milk. 



So far as known, no investigator from continental Europe has 

 become interested in determining the number of body cells present 



26 Breed, R. S. Die Wirkung der Zentrifuge und des Separators auf die Verteilung 

 der ' Zellelemente in der Milch, nebst einer Kritik der zur Bestimmung der 

 Zellenzahl in der Milch verwendeten neuen Methoden. Arch. Hyg., 75 : 383- 

 392, 1911. 



"See footnote 1. 



28 Eastes, G. L. The pathology of milk. Brit. Med. Jour, for Nov. 11, 1899, 1341- 



29 Savage, W. G. Streptococci and leucocytes in milk. Jour. Hyg., : 123-138, 



1906. 



30 See footnote 8. , , „ , 



31 Hewlett R. T., Villar, S., and Revis, C. On the nature of the cellular elements 



present in milk. Jour Hyg., 9:271-278, 1909. 10:56-92, 1910. 11:97- 

 104, 1911; 13:87-92, 1913. 



