546 Professor David James Hamilton [March 8, 



The abdominal cavity, as a rule, contains an excess of serous 

 hquicl, Init this is not always the case. Sometimes the liquid is thick, 

 muddy-looking, and, it may be, tinged with blood, while at other 

 times it is quite clear and limpid, or, at the most, a delicate coagulum 

 separates from it. In no case have I seen peritonitis or pleurisy 

 accompany the disease, and hence the conclusion seems inevitable 

 that the organism which causes it is not possessed of inflammatory 

 tendencies. 



A few punctif orm haemorrhages may be met with along the course 

 of the intestine, but with this exception all the viscera may seem to 

 be quite healthy. Nor have I seen any evidence of meningitis or 

 other disease of the central nervous system. 



The microscopic examination of the natural liquids and of the 

 organs of the body proves equally disappointing. Thus the blood is 

 free from any micro-organism which can be detected microscopically. 

 and when cultivated aerobically or anaerobicaUy remains equally 

 barren. The cerebro-spinal liquid and nerve centres are devoid of 

 any parasite which might be taxed with a casual relationship, and, 

 for these reasons, the pathology of the disease for long remained to 

 me a problem fraught with obscurity. 



During the first season (1902), in which we conducted our obser- 

 vations at Kielder, in Northumberland, we noticed, however, that 

 two kinds of case were ])rought in to us. In the one there was an 

 excess of peritoneal liquid, which was also turbid and sometimes 

 slightly stained with Ijlood. In the other the peritoneal hquid was 

 perhaps not in excess, or, if so, it was quite clear and limpid. 



On microscopic examination of the turbid liquid it was found to 

 be teeming with a large coarse-looking rod-organism having a great 

 tendency to spore, while in the case of that which was clear and 

 limpid not a bacillus was to be detected. The rod in question had a 

 close resemblance to that of Blackquarter, and, at first, we supposed 

 that we had to do with two diseases running side by side, namely, 

 Blackquarter and true Louping-ill. 



On incubating the clear peritoneal liquid, however, in sealed tubes, 

 I found invariably that, in the space of twenty-four hours, it became 

 turbid, and when the tubes were opened, a whiff of gas escaped with 

 a small explosion. On examination of the liquid microscopically, it 

 was now found to be swarming with the same large sporing rod 

 present in the liquid which was turbid. 



This threw a new light on the whole pathology of the disease. 

 There were evidently two forms, one in which the peritoneal liquid 

 was so full of a notable micro-organism that it could be readily 

 detected V)y microscopic examination, the other in which the organism 

 was so sparsely distril)uted in the Hquid that it could not at first be 

 detected microscopically, l)ut in which the same specific rod developed 

 abundantly on the liquid Ijeing incubated at a l)ody temperature. 

 The turbid liquid was found in those animals which died within 



