BUREAU OF ANIMAL INDUSTRY. 



259 



of swine plague from which the animal quickly recovers, and is thereby 

 protected from the disease. 



It is very evident that before any safe method of protective inocula- 

 tion or vaccination can be adopted we must be satisfied as to the nature 

 of (he virus? Rabbits and mice are both subject to septicaunia, and 

 it is quite certain, from the difference in the microscopical appearance 

 of the germ described by these two investigators, that either the one <>r 

 the other had cultivated and inoculated with a septic virus. Dr. Klein 

 docs not hesitate to say that it seems probable to him that, Ma* in the 

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

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

 say, on the other hand, that Dr. Klein lias 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 through a number of cultivations in purity 

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

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

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

 easily obtained it becomes doubly important to know how to discrimi- 

 nate between them. 



In former reports I have given detailsof experiments which, if correctly 

 stated, demonstrate beyond question 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 scientitic 

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

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

 two different 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 conclusion. It 

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

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

 uncertainties. 



1. The microbe of swine plague. — As I have shown elsewhere (Science, 

 1S81, p. 155) Dr. Klein was first to demonstrate the presence of micrococci 

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

 not at that time (1870) attribute, nor has he at any time subsequently at- 

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

 published a long series of investigations in 1878 (report of the medical 

 oflicer 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- 

 nomcnon (Vet. Journal, July, 1881, p. 30*47). 



In my report for 1880 (Department of Agriculture, Special Report No. 

 34, pp. 22-24), 1 published 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 precautious before being opened, and 

 were then immediately withdrawn and hermetically sealed, contained 

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

 blood contracted a severe form of swine plague. This organism was 

 found to exist in the virulent liquids (blood, peritoneal effusion, &c.) t in 

 three distinct outbreaks of the disease which were investigated at that 

 time. This was the first discovery recorded, so far as I am aware, of 

 the existence of micrococci in the blood of the affected swine before 



