DOCTRINE OF CONTAGIUM VIVUM. 175 



days at a temperature of 39 — 33° C it is used to inoculate a 

 second generation, care being taken to use a trace only of 

 the fluid part and not to come in direct contact with the 

 original granule, which may be still discerned in the pre- 

 paration. 



The specimen representing the second generation is kept 

 in the incubator for a day or two. It is then used to inocu- 

 late a fresh preparation — Third generation. And, finally, 

 this is used for establishing a fourth generation. After 

 having been kept in the incubator a part of it is used for 

 inoculating two animals, the inoculation being carried out at 

 different times. Both these animals became smitten with 

 the disease. 



Another portion of this fourth generation was used to 

 start a fifth generation, then a sixth, a seventh, and an 

 eighth generation. With this three animals were inocu- 

 lated at different times. All three animals became diseased 

 in due time. 



In order to correctly interpret the results of this last (6th) 

 series of experiments it is important to mention that inocula- 

 tion with dried lymph, diluted far less than would correspond 

 to the third generation in the last-named experiments, is 

 followed by a negative result. 



The microscopic examination of the cultivated liquids 

 proves that these are the seat of the growth and develop- 

 ment of a kind of bacterium, which has all the characters of 

 Bacillus suhtilis (Cohn). The bacillus in our case is a very 

 fine and delicate rod, thinner than both that described by 

 Professor Cohn in hay-infusion and the Bacillus anthracis so 

 thoroughly investigated by Dr. Koch. 



Our bacillus differs also in other respects from Bacillus an- 

 thracis, inasmuch as it possesses a moving stage; the Bacillus 

 anthracis described by Dr. Koch is non-moving. Like 

 Bacillus suhtilis of hay aud Bacillus anthracis, our bacillus 

 grows under favorable conditions into long leptothrix-like 

 filaments, which occasionally form more or less complex 

 convolutions. 



In these filaments highly refractive spores make their ap- 

 pearance. These become free after the disintegration of the 

 original filamentous matrix. The fully-developed spores of 

 our bacillus differ from those of hay-bacillus and anthrax- 

 bacillus by being more distinctly cylindrical and much 

 smaller.^ According to Professor Cohn (' Beitrage zur Bio- 



^ In the figures accompanying Dr. Koch's paper on Bacillus anthracis 

 ( 'Beitr. z. Biologie d. Pflanzen,' ii, 2, 1876) the spores are represented in 

 many places as more or less spherical in shape. 



