CONTAGIOUS DISEASES OF DOMESTICATED ANIMALS. 79 



(k)es not hesitate to say that it seems probable to liini that, " as in the 

 case of the microbe of fowl cholera, M. Pasteur did not work with pure 

 cultivations of the microbe of swine fever." M. Pasteur will doubtless 

 say, on the other hand, that Dr. Klein has evidently been cultivating and 

 inoculating with the septic vibrio. Both cannot be right in their belief 

 that they have been working with the true germ, and, consequently, it 

 is very probable that both sets of hogs were not protected from the 

 genuine swine plague. Each has made many inoculation experiments, 

 each has cultivated his germ througii a number of cultivations in purity 

 as he supposes, and each believes tliat he has produced the true swine 

 plague with such cultivations; but one of tliem is wrong; vaccination 

 with tlie virus of one will fail in practice, and if the wrong virus is so 

 ea.xily obtained it becomes doubly important to know how to discrimi- 

 nate between them. 



In former reports I have given details of experiments which, if correctly 

 stated, demonstrate beyond <iuestion that the microbe of swine plague 

 is a micrococcus. These experiments were made and the accounts of 

 them published in advance of those of M. Pasteur, and the evidence 

 furnished was all that could reasonably be required to decide a scientific 

 question of this kind. Dr. Klein, however, has published evidence which 

 on its face is equally conclusive in his favor; and as it is not likely that 

 two ditterent diseases resembling each other so closely in symptoms and 

 lesions, but having such dissimilar virus, have been investigated, the 

 most reasonable conclusion is that one is mistaken in his conclusio •. It 

 is necessary, therefore, to review certain points in the investigations and 

 to bring forward such new evidence as shall be required to remove these 

 uncertainties. 



1. The microbe of swine plague . — As 1 have shown elsewhere {Science^ 

 1884, p. 155) Dr. Klein was first to demonstrate the presence of micrococci 

 in the tissues of animals that had suffered from swine plague, but he did 

 not at that time (1876) attribute, nor has he at any time subsequently at- 

 tributed, the cause of the disease to this organism. On the contrary, he 

 l)ublished a long series of investigations in 1878 (report of the medical 

 officer of the Local Government Board) from which he concluded that 

 the true germ of this disease is a bacillus, and in his last paper reiterates 

 this conclusion and asserts that the micrococcus is entirely an epiphe- 

 iiomenon (Vet. Journal, Jul^', 1884, j). 30-47). 



In my report for 1880 (Department of Agriculture, Special Beport Xo. 

 .'Jl, PI). 22-24), I i)ublished experiments showing that the blood of sick, 

 not dead, hogs, which had been received into vacuum tubes that were 

 thrust inside the vein with proper precautions before being o[)ened. and 

 were then immediately withdrawn and hermetically sealed, contained 

 micrococci and no other organisms, and that hogs inoculated with this 

 blood c(Mitra(-ted a severe form of swint' plagui'. This organism was 

 found to exist in the virulent liipiids (blood, jteritoneal etlusion, ikv.], in 

 three distinct outl)reaks of the <lisease which were investigated at that 



