8 BULLETIN 940, U. S. DEPARTMENT OF AGRICULTURE. 



is not positively known how the spores of the organisms giving the 

 test gain entrance to milk. This fact naturally decreases the utility 

 of the test. Savage recognizes this condition of affairs, and in weigh- 

 ing the value of the test rightly assumes that they might gain 

 entrance to milk from other sources, and thus would represent con- 

 tamination by material not so undesirable as manure. 



YTeinzirl seems to have overlooked the possibility of the entrance 

 of the spores of B. enteritidis sporogenes from sources other than 

 cow manure. He makes a further assumption, which from our 

 results seems to be incorrect — that of giving an average figure which 

 can be safely set up as being the number of spores per gram of 

 manure. He estimates that cow manure as it enters milk contains 

 the probable average of 10,000 spores per gram. He found that in 

 moist cow manure there may be fewer than 730 or more than 14,300 

 per gram. This is a decidedly higher figure than was obtained by 

 Savage, who estimated from 10 to 10,000 per gram. As is shown 

 in Table 2, our figures for the number of spores of B. enteritidis 

 sporogenes in cow feces are much lower than those obtained by 

 Weinzirl, and agree closely with the results of Savage. In fact, 

 our figures, on the whole, are even lower than those of Savage. The 

 manure examined consisted of samples ranging from fresh to nearly 

 air dry, the most of them, however, being decidedly moist. 



Table 2. — Number of spores of B. enteritidis sporogenes in cotv manure and feed. 



Sample 

 No. 



Cow 

 feces. 



Feed. 



Sample 

 No. 



Cow 



feces. 



Feed. 



Silage. 



Grain. 



Silage. 



Orain. 



1 



2 

 3 

 4 



5 

 6 



7 

 8 



9 

 10 

 11 

 12 



Spores 

 per gram. 

 40 

 50 

 200 

 600 



20 

 .50 

 600 

 60 



800 

 1,000 



800 

 1,000 



Spores 



per gram. 



60 



10 



400 



800 



20 

 55 

 30 

 15 



80 

 40 

 60 

 80 



Spores 

 per gram. 



13 

 14 

 15 

 16 



17 

 18 

 19 

 20 



21 

 22 

 23 



24 



Spores 

 per gram. 

 140 

 100 

 140 

 600 



20 



240 



40 



20 



20 

 140 



Spores 

 per gram. 



Spores 

 per gram. 

 30 

 20 

 40 

 35 



10 

 15 

 20 

 30 



100 

 20 

 40 



200 



















































1 



i 0--rV gram. 



The average spore content of 22 samples representing different 

 cows from herds in widely scattered parts of the country was esti- 

 mated to be 304 per gram. The number of spores was estimated 

 by inoculating several series of 5 tubes of sterile milk each with a 

 different dilution of manure in sterile water. The tubes were then 

 heated to 80° C. for 10 minutes, then cooled and incubated. From 



