REPORT OF THE BUREAU OF ANIMAL INDUSTRY. 83 



into the circulation before death as spores, and their develo'pment 

 kept in check until that took place. It is also probable that they 

 are important factors in the rapid changes which may take place 

 after death. 



In some half a dozen casos decomposition was so far advanced that 

 no thorough examination was made. At first it was thought that 

 the animals had been dead several days, but the person in charge of 

 the herd asserted that they had died during the night. Although 

 the temperature had fallen below 30 F., decomposition was far ad- 

 vanced. It may be that the live animals crowded upon the dead and 

 thus kept the body warm. Yet this supposition is not capable of 

 accounting for the rapid changes. The hemorrhagic lesions may 

 have enabled various bacteria to become distributed throughput the 

 body. The heat disengaged by them during multiplication, aided by 

 the warmth of the litter, may have been sufficient to keep up the 

 process of decomposition. This post mortem growth may also ac- 

 count for the large number of hog cholera bacteria found in many 

 spleens, although the temperature of the air was, as a rule, far below 

 the point where multiplication may^ take place. 



Buzzards may carry the disease from one place to another. When 

 the dead animals were at all exposed to view they were immediately 

 attacked. Whether hog cholera bacteria are entirely destroyed in the 

 digestive tract of these birds can not be said, but there is nothing in 

 the range of our knowledge of bacteria which will exclude the proba- 

 bility that the bacteria are not all destroyed during the digestive act, 

 and that they may be scattered about by these birds. Such observa- 

 tions should strongly urge all persons who have charge of dead ani- 

 mals to bury or burn them immediately, or to have them destroyed 

 in some other effectual manner. 



SOME EXPERIMENTS ON THE LENGTH OF TIME DURING WHICH HOG 

 CHOLERA VIRUS REMAINS ALIVE IN THE SOIL. 



The virus of hog cholera is quite tenacious of life, in spite of the 

 fact that no spores are formed. In the report for 1886 it was shown 

 that hog cholera bacteria remained alive in ordinary sterilized drink- 

 ing water for about four months. They resisted drying under cer- 

 tain conditions for nearly two months. During the past year some 

 preliminary experiments were made concerning the vitality of hog 

 cholera bacteria in the soil. This becomes infected during epizootics 

 of this disease by the discharges of the sick perhaps more thoroughly 

 than anything else in the surroundings of the animals. Moreover, it 

 is the most difficult to disinfect, as we have no knowledge of the 

 depths to which the living virus may be carried by water. If it can 

 be shown that the life of such virus in the soil is speedily destroyed, 

 the precautions to be taken would be quite different from those needed 

 if the virus exists for a long period of time. 



The experiments undertaken to solve this question are not com- 

 pleted, but the results thus far obtained are sufficiently definite to 

 warrant publication. 



A small flower-pot containing soil was sterilized by moist heat and 

 protected from drying and dust by a large bell jar. On its surface 

 about 100 cubic centimeters of a bouillon peptone culture of hog 

 cholera bacteria was poured and the whole maintained moist and at 

 the laboratory temperature. The soil used was a very fine loam from 

 the grounds of the Department of Agriculture. 



