512 KEPOKT OF THE COMMISSIONER OF AGRICULTURE. 



WHS evidently sick the next day, but slowly recovered. The others did 

 not show any symptoms of illness. 



January 11, the one Avhich had received a hypodermic injection of the 

 simple culture liquid (No. 7), and the one which had received the largest 

 dose of heated virus (No. U), received subcutaneously about .15^'' each 

 of a liquid culture live days old, which had been i)repared from a ])o- 

 tato culture fifteen days old. It is probable that this virus was not 

 so strolls', therefore, as a more recent culture from the i>ig" would have 

 been. Both pigeons were sick on the followiug day. No. 7 died seven 

 days after inoculation. The bacterium of swine plague was found abuu- 

 dautly in the pectoral muscle, in the sjileen, kidneys, and liver in mod- 

 erate numbers.* The other pigeon (No. 9) slowly recovered, but had 

 lost the use of its legs. It seemed perfectly well when killed, fifteen 

 (lays after inoculation. It was quite fat, the crop filled Avith food, in 

 the pectorals were found imbedded two elongated masses of dead tissue 

 or sequestra about 2'='" long and I*''" in diameter, entirely separated from 

 the sorrounding tissue by a dense, smooth membrane. In this animal 

 the multiplication of the pathogenic bacteria was purely local, the re- 

 sistence of the tissues being sufQcicntly powerful to confine and finally 

 destroy the bacteria. The sequestra were made up of dead muscular 

 fibre, which was pale and parboiled in appearance. Each was envel- 

 oped b^' a more or less hyaline homogeneous layer. A liquid culture, 

 iuoculatcd.witli blood from the heart, remained sterile. 



This experiment pointed evidently to an immunity obtained from the 

 chemical products of the bacterium of swine plague. To confirm this 

 view another cxi)eriment was made. 



January 21, three pigeons (Nos. 11, 12, 13) received. hypodermically 

 l.a'^*^ of heated culture liquid in which the bacterium of swine plague 

 had nnilti plied for two weeks, and was then destroyed by exposure to 

 58° to 00° G. for several hours. A fourth pigeon (No. 14) was kept as a 

 check. No. 10, which had received .4°*= of heated virus December 24, 

 now received a second dose, this time of 1.5*^°. For the following three 

 or four days all were somewhat ill, and remained rather quiet, with 

 feathers slightly ruffled. 



January 29, when all seemed well, three of the four (Nos. 10, 11, and 

 12) received hypodermically another dose of l.o'^^ of heated culture 

 liquid. The otlaer (No. 13) had been fiercely attacked by its fellows, and 

 its head was so injured that it was thought best not to give it an in- 

 jection at this time, and it was placed in a spacious coop alone. None 

 of the birds seemed much afiected by this dose. 



February C, a final injection was practiced upon the four, No. 13 hav- 

 ing recovered from the effects of its injuries. The dose was, as before, 

 1.5'^<=. All seemed well a few days later. 



February 13, one week after the last injection, these birds were in- 

 oculated with strong virus, the quantity injected being. 75'=°, which had 

 hitherto proved invariably fatal, with the single exception of the bird 

 that had been previouely treated with heated virus. Those inoculated 

 were Nos. 10, 11, 12, and 13, which had received the heated virus, also No. 

 14, the check pigeon, which had not been touched, and No. 8, which had 

 received a small quantity, 8°*^ of heated virus, December 21, over fifty 

 days before. 



'' la tlu8 animal tlio major part of both pectoral uiusclcs appeared as if tlicy Isad 

 been boil. hI ; tlioy weio ^vLi^isll, bloodless; tlio fibers conld be easily liidkcii ami 

 crushed with the forceps. The muscular tissue .surrouudiiijjf the dead purtiou was 

 very dark, gorged ^vitll blood. Tlio liver was darlc in pateliee; sploeii and kidney 

 pale. 



