200 



all other tissues and organs the blood stream of the 

 arteries supplying them is ultimately spread through- 

 out their substance by means of a dense network of ex- 

 cessively minute vessels called capillaries, from which 

 it is, so to speak, collected by the veins leading from 

 the said organs or tissues. In the spleen these capil- 

 laries are absent ; the blood on being discharged into 

 its substance from the terminal twiglets of the splenic 

 artery permeates the spleen pulp like water in a boggy 

 field before being gathered up by the receiving twiglets 

 of the splenic vein, preparatory to its being carried 

 into the liver by the portal vein. The bacilli therefore, 

 lying about as it were in this stagnant morass, and 

 being while in this situation somewhat relieved from 

 the inhibitory action of the antitoxins in consequence 

 of the structural changes going on in the blood, (for 

 the spleen is apparently a kind of repairing yard in this 

 respect), have greatly enhanced chances of multiply- 

 ing at a rate denied to them in the liver. Not only 

 are most of them mechanically arrested in the spleen, 

 but those which are carried on have to contend with 

 the antitoxic process already alluded to as existing in 

 the circulating blood. 



Such is the position of affairs at this stage of the 

 disease, and here again I must revert to my previous 

 warnings, even at the risk of prolixity. Nothing that 

 we can so far distinguish with the 7iaked eye or even with 

 the lower power objectives must be taken as positiveh' 

 indicative of septicaemia. Livers and spleen are fre- 

 quently congested and enlarged from other causes. 

 When therefore we are told that a bird has died of 

 septicaemia merely on such naked eye evidence as the 

 above, or as I before said on the grounds of putridity, 

 which are even more fallacious, we know that this state- 

 ment is open to very direct question. And also when 

 on a like naked eye authority we see the converse, viz. 

 that such and such a bird's liver etc. was congesed or 



