BUREAU OF AXIMAL INDUSTRY. 521 



tills form tliat It appeared the lirst time to j\DI. Pasteur and Thniliier. 

 How the vrritcr could have spoken of it in tliis way while acknowknlu- 

 ing- at the same time the work of Lydtinand Schottelius, who describe 

 it as an uudoubted bacillus, seems iucompreheusible to us. It ai)])ears 

 impossible that any one acquainted with the appearance of the bacillus 

 of rougct in the tissues and cells of an aflccted animal or in liqiiid 

 media conld describe it under the form of an elongated hgure-of-eiiilit. 

 Both Eoux and Schiitz {Loc. cit., p. 75) describe the microbe of roufjct 

 as non-motile. Schottelius, who agrees with Schiitz in almost every par- 

 ticular concerning the characters of the bacillus of roiiget and those of 

 Pasteur's vaccine, describes the bacillus as motile. We have not seen 

 any spontaneous movement in the cultures obtained from the vaccine, so 

 that we feel inclined to believe that the cultures examined by Schot- 

 telius were impure. 



Tlie perplexing and- conflicting descriptions given by the French ob- 

 servers arc most charitably explained by assuming the existence of two 

 liitherto undifierentiated diseases, that of rouget and swine i^laguc 

 pioper. It may l»e that the foreign bacteria frequently found in the iii- 

 lernal organs in swine plague have contributed to the general confusion. 

 It may be that animals suii'ering from swine plague have been invaded 

 by the bacillus of roiigcf, which is much more abundant in the various 

 organs than the organism i)roduciug swine iilague. 



CONCLUSIONS. 



The preceding investigations defuiitely settle certain controverted 

 points concerning the etiology of swine plague, wliich may be briefly 

 summarized : 



(1) Swine plague is caused by a specific microbe multiplying in the 

 body of the diseased animal. The microbe probably belongs to the 

 genus bacterium, and has the power of spontaneous movement. ' It is 

 easily cultivated in nutritive liquids, but grows less readily on gelatine, 

 which it does not liquefy. 



(2) When introduced beneath the skin, this bacterium is fatal to pigs, 

 rabbits, guinea-pigs, mice, and a certain percentage of pigeons. It is 

 also fatal to pigs when introduced with the food or when they feed on 

 the internal organs of swine which have died of the disease. 



(3) The disease described in France as rouget, in Germany as Eoth- 

 hnif, and for which Pasteur has prepared, a vaccine, is caused by an en- 

 tirely difl'erent microbe. The vaccine for this disease does not protect 

 against swine plague. 



(4) The introduction of Pasteur's vaccine is not only useless, but may 

 contribute to the introduction and spread of a disease, the existence of 

 which in this country has not yet been demonstrated. 



