BY DR. OSCAR KATZ. 563 



The third crow whrch also was ill since the previous evening, was 

 found dead at 7.30 p.m., April 10th ; lying on the floor ; it must 

 have died between 5.50 p.m. and that time. 



(A vigorous full-grown rabbit, also inoculated with | ccm. of that 

 liver-blood, as control, was found dead at 7 a.m., April 9th. It 

 must have died soon after 10 p.m., the previous night.) 

 The examination of the carcasses of the three crows, of which the 

 last two were in a very good condition, resulted in showing 

 that they all had succumbed to chicken-cholera. The carcasses 

 were very stiff. At and round the seat of inoculation there was, 

 in the case of the last two crows, a tough, yellowish- white forma- 

 tion, resembling in appearance what is known in fowls or pigeons 

 similarly treated. Spleen conspicuously enlarged, cherry-brown, 

 and soft. Intestines hyperaemic ; hsemorrhagic exudations in the 

 duodenum of the crow which died first. Blood mostly coagulated, 

 blackish ; in it innumerable numbers of the typical bacteria of 

 chicken-cholera. 



To judge from the outcome of these experiments we may say, 

 generally, that the microbes of chicken-cholera are only under 

 certain conditions fatal to crows. Small doses of the virus, it 

 appears, are not efficacious enough to become fatal ; on the other 

 hand, repeated feedings on larger quantities of virulent material 

 are more dangerous, while inoculations with larger quantities of 

 such caused death (from chicken-cholera) each time. The pre- 

 vious treatment of the crows mentioned under iii and iv, may 

 have had something to do with the surviving of the greater por- 

 tion (iii), or of all of them (iv). These treatments combined, 

 were, however, unable to protect — if there was any protection at 

 all — the three crows, when they were subjected to a severer test, 

 about four months later. 



How far there is danger for all the useful indigenous birds to 

 take up the disease (chicken-cholera), should the latter be intro- 

 duced into the country for the sake of rabbit-destruction, cannot 

 be precisely defined from the results of the above experiments. That 

 such a danger, however slight it may be, does exist, if the disease 

 was intentionally spread and reared in the open, cannot be denied 

 by the unprejudiced mind \ and that, even admitting that in the 



