THE ALIMENTARY CANAL AS A SOURCE OF CONTAGION 3 1 



symptoms having been the effect of the introduction of the serum, but 

 then it is to be remembered that Louping-ill is a fairly chronic 

 malady, that it sometimes runs a course of four, five, or six weeks, and 

 that, in these cases, the nervous symptoms are best marked. We have 

 also noticed that where the administration of the organism by the mouth 

 has communicated the disease the symptoms have not shown themselves 

 for a fortnight to a month afterwards. The poison of Hydrophobia 

 requires an even longer period of incubation, and the symptoms in it, 

 as in Louping-ill, are largely of a nervous character. 



Had the animal died from tetanus we should have had to fall back 

 on the disesase being of the so-called "idiopathic" variety to account for 

 what happened in our experiment, a disease of whose pathology nothing 

 is known. Indeed, these examples of " Louping-ill tetanus " open up the 

 whole question of what " idiopathic tetanus " in the human subject means. 



Anaemia. 



The study of this exceedingly interesting group of diseases in the 

 sheep, and of chorea paralytica in particular, naturally leads one on to 

 inquire whether there are any analogous diseases in the case of man. 

 Each member of the group is caused by an anaerobic sporing bacillus 

 whose natural habitat is the intestine, and which, under certain conditions 

 of body, passes through the intestinal wall, and gets into the peritoneal 

 cavity. 



The anaerobic bacteria, naturally present in the human intestine, 

 seem to include some highly pathogenic members which only require 

 the proper surrounding conditions to enable them to call forth their toxic 

 action. And, in the first place, certain of them have an extraordinarily 

 powerful haemolytic action. In the case of the group of pathogenic 

 anaerobes parasitical on the intestine of the sheep, which we have been 

 considering, there are also some whose haemolytic action is intense. 

 Among these may be mentioned Braxy and Disease "A." The organism 

 in each of these diseases is so haemolytic that sometimes not a single 

 coloured blood-corpuscle will be found in the blood contained in the 

 heart. When the organism of either of them is grown anaerobically on 

 sheep's blood in vitro during the season at which these diseases prevail, 

 the haemolytic action is so profound that every blood-corpuscle may have 



(31) 



