COISTTENTS. 
Page 
Object of the work 5 
Inevitable impurities in bovine virus 6 
Object of glycerinating the vaccine pulp 6 
Seasonal variation in the purity of vaccine virus 8 
Technique employed in counting bacteria in vaccine virus 11 
Number of bacteria in vaccine virus, with a special study of the pyogenic 
cocci 12 
Series I. Kesults of studies made during the winter of 1901 13 
Series II. Eesults of studies made during the summer (April and May) of 
1902 19 
Series III. Eesults of studies made during the winter (November and 
December) of 1902 27 
Dry points and glycerinated virus compared from a bacteriologic standpoint. . 38 
Experimental tetanus in vaccine virus 38 
Viability of tetanus in vaccine virus - 39 
Virulence of the tetanus culture used 39 
Viability of tetanus spores in pure culture in glycerinated virus 40 
Viability of tetanus spores in pure culture on dry points 43 
Viability of tetanus spores in mixed culture in glycerinated \drus 45 
Viability of tetanus spores in mixed culture on dry points 47 
Summary and conclusions 48 
3 
V 
