CONTAGIOUS DISEASES OF DOMESTICATED ANIMALS. 369 



that there seemed no reasonable giounds for doubting the entire success 

 of the inoculation. In order to confirm this, however, and i)lace the 

 matter beyond doabt, the Ibllowiug' experiment was undertaken : On 

 February 19, 1879, a healthy pig was inoculated with the congested 

 lymphatic glands and lungs*of the above-mentioned rat. On the sixth 

 (iay after inoculation there was much malaise, with redness of the 

 skin and the appearance of the black unctuous exudation on the 

 ears and legs. These went on increasing, and black spots and patches, 

 ineffaceable by pressure, appea-red on the inside of the thighs and hocks. 

 The subject was destroyed on the twentieth day, and showed the usual 

 symptoms of the disease. The lesions were as unequivocal as in any 

 case where inoculation was made iromasick pig direct, and would seem 

 to i)rdYe conclusively that the rat is capable of containing this disease 

 and of conveying it back to the pig. 



The above is a brief resume of the results of the more important ex- 

 periments undertaken and completed by Dr. Law after the closing of 

 his report last season. In view of the recent discoveries of M. Pasteur 

 and other eminent scientists in inoculations for charbou and anthrax, a 

 brief mention of which is made in Special Eeport ISTo. 22, Dr. Law is now 

 engaged in a like series of experiments to determine if diluted inocula- 

 tions will not produce swine plague in a mild form and in such manner 

 as to guarantee immunity from a second attack. 



SECO]S"D EEPOET OF DE. H. J. DETMEES, V. S. 



Hon. W3I. G. Le Due, 



Gommissioner of Agriculture : 



Siu: After I sent you my supplemental report, dated December 1, 

 1878, you ordered me to go to work again and complete the investiga- 

 tion of swine plague, begun under j-our directions on August 1, 1878. 

 In compliance with this order I at once started for a field of operations, 

 and arrived at Dixon, Lee County, Illinois, on December 28. After a 

 brief survey I established my experimental station at Gap Grove, a 

 small village six mdes west of this place, and at that time the center 

 of an infected district. I remained there until February 8, 1879, when 

 you orcftred me to the Union Stock Yards of Chicago, to i aspect cattle. 

 My investigation, in consequence, was thereby interrupted, until on the 

 IGth of May, 1879, when you requested me to resume my former work. 



The results of my work in investigating swine plagrie from December 

 15 to Februry 7, and from May 18 to July 4, will be found briefly 

 reported in the following pages : For convenience and to avoid unnec- 

 essary repetition, I shall arrange the vaiious chapters in the same 

 order as in my first report, and shall exclude, as much as possible, 

 everything already stated in the latter. The tbllowing chapters, there- 

 fore, may be considered as supplementary to those of my first rex)ort. 



1. DEFINITION OF SWIXE PLAGUE. 



]S"othing new needs to be added, except that swine plague, although 

 a disease sui generis^ peculiar to swine, can be transferred by inoculation. 

 and undoubtedly, also, by means of infected food and water, to other 

 animals, such as rats, rabbits and sheep (Prof. J. Lav,), cattle and dogs, 



2-1 AG 



