1881.] On the Infectivity of the Blood and other Fluids. 453 



very few minutes, rendered it necessary to obtain it with the least 

 possible delay. In the latter cases, i.e., of transmitted infection, where 

 the period of incubation is constant within a few hours, it is easy to 

 watch the death of an animal and examine it immediately ; but in the 

 case where it is originated by putrid matter, this period varies within 

 comparatively wide limits, death perhaps occurring during the night 

 or when not expected. It is then more difficult to obtain it before 

 coagulation occurs, and hence several failures were experienced in 

 endeavouring to prepare successively diminishing quantities of the 

 blood of this generation by fractional dilution. 



Experiments. 



Infection was originated in a young rabbit, No. 1, after some previous 

 failures, by injection under the skin of the back of 3*0 gtt. of putrid 

 bullock's blood, diluted, the animal was found dead forty hours after 

 inoculation, with the appearances mentioned as usually occurring in 

 these cases. Around the site of injection was observed diffuse 

 hyperemia, with extravasation of blood from the small vessels, a 

 marked induration and discoloration of the subcutaneous tissue at the 

 same spot, which appearance I have found invariably whenever 

 infection occurred. There was no oedema, nor, beyond congestion, 

 was any change in the spleen or other organs apparent. The blood 

 on examination was much coagulated ; in that of the heart were found, 

 though irregularly distributed, numerous micro-organisms, a form of 

 bacterium hereinafter more particularly referred to. These were not 

 found in this or subsequent cases in any of the organs or other tissues, 

 but as they are minute, and even in the blood when unstained, are 

 difficult to recognise, in other tissues they may easily escape observa- 

 tion. The case of this rabbit so intoxicated by putrid blood, I have, 

 in accordance with the phraseology of Davaine and other previous 

 writers, termed the first generation of infection, though obviously for 

 the reasons referred to, it would be more strictly accurate to designate 

 such animal, as itself, not infected but poisoned, and originating 

 infection. 



Another rabbit, No. 2, thereupon received in like manner by injec- 

 tion, one drop diluted of the blood of No. 1. It died within twenty- 

 four hours ; blood from its heart was immediately diluted to different 

 degrees, and ten drops of the various dilutions were injected into five 

 other rabbits, all of similar size and condition, so that they received 

 respectively the following quantities of blood, viz. : — No. 3, T yt n gft- ; 

 No. 4, ^th gtt. ; No. 5, ^th gtt ; No. 6, y^ooth gtt. ; and No. 7, 

 10 oo QQ-th gtt. No. 3 died in 25 hours, No. 4 in 24 hours, No. 5 in 

 25 hours, No. 6- within 40 hours, and No. 7 in 27 hours ; all, with the 

 exception of No. 6, in my presence, and all with very similar 

 symptoms ; thus showing (1) that in this form of septicheemia the 



vol. xxxiv. 2 H 



