516 EEPORT OF THE COMMISSIONER OP AGRICULTURE. 



rouget, which prevails abroad, but most probably does not exist in thi3 

 country. 



iSicine plague and typlwid fever. — Eecent investigations* have shown 

 quite conclusively that there is constantly present in tlic internal or- 

 gans of persons who have died of typhoid fever a sliort bacillus, about 

 three times as long as thick, equivalent in length to one-third the diame- 

 ter of a red blood corpuscle (about 2.3 micromillimeters). This bacillus is 

 spore-bearing, and does not stain so readily as most bacteria. It is mo- 

 tile, but does not liquefy gelatine. It grows on i^otato and in blood 

 serum. Injected into rabbits, mice, guinea-pigs, and pigeons it produces 

 no efiect whatever. In comparing with this organism the bacterium of 

 swine i^lague we are at once set at rest as to the non-identitj" of the two 

 diseases. These organisms resemble each other in that both are motile 

 and fail to liquefy gelatine. They differ in size, in the habit of forming 

 spores, and in the manner of growing on potato. More important than 

 this, however, is the difference in the effect on the lower animals. The 

 bacterium of swine plague is fatal to guinea-i^igs, rabbits, mice, andi)ig- 

 eons, in the order named. The bacillus of typhoid fever has no effect on 

 these animals. What the effect of the bacterium of swine plague would 

 bo in the alimentary canal of man is a matter of extreme importance to 

 the public health, but cannot be determined experimentally from the 

 nature of the case. That it would have some disturbing effect is highly 

 I)robablo. 



OTHER INVESTIGATIONS OF ROUGET AND SWINE PLAGUE. 



In Pasteur's first communication on rouget {Comptes Eendus, 1882, 

 XOV, pp. 1120, 1121) he describes as the cause of the disease a microbe 

 having the form of a ligure-of-eight and resembling the microbe of fowl 

 cholera, but smaller and less easily seen. He speaks of it as being easily 

 cultivated. It kills rabbits and sheep, but has no effect on fowls. In a 

 second communication, made about a year later (Loc. cit., 1883, XOYII,* 

 pp. 1163-1160), he confirms the statements made in the preceding commu- 

 nication and describes the methods which he adopted to obtain an atten- 

 uated virus or vaccine. If a series of pigeons, which are susceptible to 

 the virus, be inoculated, one from the other, the virus obtained from the 

 last pigeon is more potent than that derived from swine. If, in the same 

 way, a series of rabbits be inoculated, the virus from the last animal of 

 the series is much weaker than the original virus from swiue, and when 

 the latter are inoculated with it they do not die, but are made sick, and 

 henceforth are protected from the disease, or, in other words, vaccinated. 

 It is established beyond a doubt by our own investigations and those of 

 others during the past yearj:hat the microbe looked upon by Pasteur as 

 the cause of the disease, and cultivated for purposes of vaccination, is a 

 bacillus which cannot be described as a figure-of-eight form by any means. 

 It would be interesting to know whether the original microbe discovered 

 by Thuillieris not really identical with the form which we have described 

 as being the cause of swine plague, and which in general ai^pears under 

 the form of afigure-of eight when obtained directly from the spleen and 

 properly stained. It remains still to be determined whether the diseases 

 known as rouget and swine xdague exist together on the continent. If 

 they do it is highly probable that Pasteur has studied two microbes, the 



*Gaffky: Zur JEtiologie des Ahdoni%naltyj}lms. Miitheilungen a. d. Kaiserlichcn Ge- 

 eundheil sarnie. Bd. II, S. 372. 



