54 MICRO-ORGANISMS AND DISEASE. [CHAP. 



cultivated, and with which he produced septicaemia in rabbits, 

 may perhaps be a bacterium identical with the above, but 

 this is not definitely settled. 



(b) Bacterium of Davaine' s septicaemia. This is a bacterium 

 which was originally derived by Davaine l from putrid ox- 

 blood in the warm season. Injected into rabbits, it produced 

 rapidly fatal septicaemia, of the same nature as in the case 

 just mentioned, the blood teeming with a similar kind of 

 bacterium as in Koch's septicaemia just described. The 

 smallest quantity of the blood is again rapidly fatal in its 

 action. It is distinguished from Koch's septicaemia in the 

 rabbit by this, that Davaine's septicaemia is easily transmissible 

 to guinea-pigs, but not to birds. 



Dowdeswell 2 has shown that when such blood is thoroughly 

 sterilised (i.e. when the bacteria are killed), it has no longer 

 any infective power. Davaine had first shown that the blood 

 of rabbits dead of this form of septicaemia bears an enormous 



Fio. 34. Brxxm OF RABBIT, DEAD OF DAVAINE'S SEPTICAEMIA. 



amount of dilution without the minutest quantity of it losing 

 its pathogenic properties. Dowdeswell has shown that this is 

 easily explained by the enormous number of bacteria present 

 in every drop of the blood. But it has been sh wn by Gaffky 

 and Dowdeswell that there is no increase in the virulence of 

 the virus when it is passed through successive animals, as was 

 maintained by Coze and Feltz. 3 



(c) ^Bacterium of fowl-cholera (microbe du cholera des poules). 

 Semmer, Toussaint, and Pasteur 4 have shown that this 



1 Pull, d VAcad. de Med. If 72. 



8 Proceedings of the Royal -Society, No. 221, 1882. 



3 Strasburg, 1866 ; Paiis, 1872. 



4 I place this here as a bacterium, but it is not quite decided, and not quite 

 clear from Pasteur's description, whether the microbe is only a microeoccuR 

 dumb bell, or a bacterium termo. Compare also Semmer (Verqleichende Patho- 

 lr>(jie, 1878), Perroncito (Archiv f. Wins. u. pract. Thierheilk., 1879). Toussaint 

 (Comptes Rendus, xci. p. 301) considers the disease identica 1 with Davaine's 

 septicaemia. I am inclined to think thai Pasteur has not used pure cultivations , 



