642 Veterinary Medicine. 



len, has been charged with arousing " hay fever," but though 

 very common in Europe it has never been charged with producing 

 anything like the Pictou cattle disease. The coincidence of the 

 plant and the disease is manifestly a mere accident. Professor 

 Lawson, of Halifax, investigated the flora of the district but was 

 unable to find any poisonous plant to which the mortality could 

 be attributed. D. McEachran tells us that many farms are 

 covered with the ragweed, so that it is abundant in the hay, yet 

 they are absolutely free from the disease. 



The idea of a mineral poison must be dismissed in the same 

 way. Pictou lies on the Silurian formation with abundant coal 

 fields, and the chemical analyses made for McEachran were en- 

 tirely fruitless of results. 



Wyatt Johnston investigated the question of communicability 

 by contagion from animal to animal, but he found that neither 

 contact, nor inoculation produced positive results. Nothing 

 positive has come of investigations into the possible micro-biology 

 of the disease. In blood from the jugular vein of a cow suffer- 

 ing from the disease, Thayer and McEachran found bacteria, 

 under an object glass magnifying 600 diameters. Wyatt Johnston, 

 " in a series of pretty exhaustive bacteriological examinations, in 

 which all the tissues, including the blood, the spleen, the kidneys, 

 lungs, and the fluids from the lymph glands" were employed, 

 failed to find any constant or characteristic organism. 



Attacks are very rare in winter, the disease usually appearing 

 in the warm summer months, from June to August, and after the 

 animals have been some time at pasture. This might lead to the 

 suspicion of bacteria or other microbe on the growing vegetation ; 

 or of some insect enemy which, maturing at that season, transfers 

 the poison from animal or other source to animal ; or of some 

 poison, vegetable or mineral, which acts injuriously on the liver, 

 and which can only be had in the pasture. This, however, is 

 mere hypothesis. 



Eiver affections are common in hot, damp seasons, but Pictou 

 and Antigonish do not differ in climate from other counties in 

 Nova Scotia, and much less do the infecting farms from those 

 adjacent. 



McEachran compares the disease to what occurs in the human 

 being during famines, from the ingestion of innutritions and un- 



