292 SUMMARY OF EVIDENCE OIST PLEURO-PXEUMONIA. 



It is acknowledged that it is impossible to diagnose the disease 

 during the incubative period. It is also acknowledged that it 

 is extremely difficult, and sometimes impossible, to diagnose it 

 when it has assumed the chronic or encapsuled form, especially 

 where the lesion is a small one or deeply seated. 



It is generally believed to be a micro-organismal disease, and 

 it has been asserted that the organism has been detected in the 

 lung lesion, and that it has been cultivated in nutritive media 

 outside of the animal body. The organism is thought to be 

 present in the blood during the incubative period, or at least 

 during the fever stage ; and these facts point to the probability 

 that it might be possible to diagnose the disease by making 

 cultivations of the organism contained in the blood before it 

 is possible to diagnose it in any other Way. Whether that may 

 be or not, it is admitted that it would be of great importance 

 to discover a method by which the disease might be detected 

 before it becomes infectious. 



It seems to be the opinion of most veterinary surgeons that 

 the disease is not infectious until after the incubative period, for 

 they give it as their opinion that, in the event of their being 

 free to slaughter a suspected, but not pronouncedly diseased, 

 animal, they would be much better able to check the disease, 

 and even to prevent its transmission through a herd. 



It is not exactly known how the disease is transmitted, but it 

 is suspected that the organism of infection passes directly in the 

 air from one animal to another. No medium of transmission has 

 been discovered, though several have been suspected. 



It is not known if a place can harbour infection after the 

 removal of the infected animal, but those who have had an out- 

 break in their place are prevented from re-stocking it for fifty- 

 six days, on the supposition that it can. It is not known if any 

 disinfection of stalls, litter, or dung is at all necessary. If 

 necessary, it is not kno^vn what is the simplest, most effective, 

 and least expensive method of disinfection. 



It is not known that the dung or litter of a diseased animal 

 can communicate the disease, but it is usual to consider that it 

 is so, and therefore to bum or otherwise destroy it. The cost to 

 the ratepayers and the inconvenience and loss to the farmer 

 from the destruction of his dung is very great, and may be 

 entirely unnecessary. 



Regarding inoculation, much has to be discovered, so as to 

 render it a safe and successful operation. 



It is not known whether the method of seton at present em- 

 ployed is the best one. It has not been compared with any 

 other good method. 



It is not known why it is that inoculation is followed by 

 serious consequences in some cases and not in others. 



