320 BULLETIN No. 161 [November/ 



of fresh manure were obtained. The manure from this cow had 

 been tested a number of times for tubercle bacilli by making sub- 

 cutaneous inoculations of i cc. of a 2 percent emulsion of the 

 fresh f eces. Upon four occasions such tests gave negative results ; 

 three other tests, made respectively August 31, 1909, July 18, 

 1910, and August 16, 1910, produced tuberculous guinea pigs. 

 The guinea pigs in none of the three tests became severely tuber- 

 culous ; and two of the guinea pigs, one each in the last two tests, 

 remained healthy. The last testing, August 16, 1910, was made 

 on the day of exposing this sample of manure to the weather. 

 Tho the infected guinea pig from this sample did not show severe 

 tuberculosis when killed and examined 80 days after inoculation, 

 a second guinea pig inoculated w r ith the diseased tissue from this 

 guinea pig showed severe generalized tuberculosis when killed and 

 examined 38 days later. 



EXPOSURE OF miect ed manures were taken to a secluded 



SAMPLES plot of ground on the Experiment Station farm 



for exposure. The manure infected with pure 

 culture of bovine tubercle bacilli was divided into two equal parts. 

 One half' was placed in a free, open place, fully exposed to the 

 sunshine thruout the whole day. This part, flattened out into a two- 

 indi layer, was placed upon a sod with the grass cut short. A 

 one-inch mesh poultry netting was placed over the infected manure 

 in order, especially, to keep out the English sparrows, so that 

 they could not carry upon their feet this infected manure to the 

 stock upon the Experiment Station Farm. 



The other part, protected from the sunshine, was placed a few 

 yards from the former on the north side and very near a bank of 

 earth six feet high. The ground upon which this manure was 

 exposed was first made smooth by removing the sod. The manure 

 was then spread in a two-inch layer just as was the part exposed in 

 the sunshine. To protect this sample further from the light, an em- 

 bankment of soil was made one foot high on three sides, and was 

 covered over with a bunch of weeds. Tho the soil was more 

 moist than in the plot where the part was exposed in the sunshine, 

 it was not more moist than that usually found in a shady place. The 

 layer of infected manure in this protected place dried on top in 

 a week's time to a hard crust, but the bottom always remained 

 moist. The manure from the tuberculous cow was divided into 

 two parts; one part was placed in the sunshine, and the other in 

 the place protected from the sunshine, very near the two artificially 

 infected samples and exposed in the same way. 



