



jaws sometimes remain rigid, the head and neck extended. In equines cramps are 

 not infrequent, a limb is slowly extended as far as possible, remaining in that position 

 for a short time, then slowly and extremely flexed, held high above the ground for a 

 minute or more, the animal moving off at a limp. The contractility of the muscles 

 is delayed, slow, and hesitating, not arrested at the proper moment, resulting in over- 

 flexion and extension. This might be explained by absorption of, pressure on, or 

 breaks in the continuity of the protoplasm of the muscle fibres by the Sarcocysts, and 

 consequently, a greatly reduced conductivity. . It is equally true, that the origin of 

 this muscular disturbance may be seated in the nerve cells of the brain, as a result 

 of loco-poisoning. If the latter hypothesis is correct, it is a strange coincidence that 

 in the few cases examined the muscles most affected were those in which the parasites 

 were most numerous. It is difficult to trace any relationship between the disease of 

 the osseous structures of the jaws and face and the disease of the muscles; and yet, 

 as mentioned before, Laveran and Mesnil isolated an extremely- active poison from the 

 Sarcocystis-tenella of the sheep (unfortunately, the original publication by these 

 savants is not a hand) and it is' permissable to assume that a similar toxine is 

 elaborated by the parasites infesting the ox and horse. Sarcosporidiae appear more 

 Numerous in ' locoed ' oxen than in horses, in the latter intestinal parasites are 

 exceedingly plentiful, and very formidable-looking verminous aneurisms have been 

 found at each autopsy. The condition favourable to these parasitic invasions may 

 very likely originate from ingestion of the loco-weed, and possibly to some other 

 dietetic conditions peculiar to the ranges where loco-disease prevails. It might be 

 mentioned in passing that the writer has on several occasions examined specimens of 

 meat, purchased from a local butcher, for Sarcosporidiae. In all, three ox-hearts, an 

 ox-tongue, and several joints of beef have been examined, each specimen being from 

 a different animal. Of these only one was found infected with Sarcosporidiae, a heart, 

 the parasites being very numerous. This heart looked decidedly unhealthy. There 

 were a few fibrinous growths on the epicardium, considerable gelatinous cedema, and 

 the little fat remaining, very soft and yellow. 



Concerning the Parasite, Sarcocystis. 



Class — Sporozoa; sub-class — Neosporidiae; Order — Sarcosporidiae; Genus — Sar- 

 cocystis, Eay Lankester. (After Minchin.) Infecting domestic animals there are 

 probably several distinct species of Sarcocystis, but these have not been clearly differ- 

 entiated. 



In those infections of the horse and ox, already described, and even in the most 

 heavily infested cases, very young forms of parasites could never be found; only the 

 trophic phase was met with, accompanied by spore-production, as in all of the sub- 

 class of Neosporidiae. In cattle the youngest trophozoites observed were lodged in the 

 muscle fibre, and, though microscopically invisible, had attained a considerable size 

 and formed several hundred spores. The larger parasites, distending the muscle fibres, 

 are just visible to the naked teye as minute whitish rods or 'specks. In the equines, 

 Cases VII. and VIII., the parasites averaged a much smaller size than in the bovines, 

 the smaller trophozoites containing only the spore mother-cells or pansporoblasts, 

 preliminary to sporulation. In these young forms the radially striated enveloping 

 membrane is well marked (Plate I., fig. 3) ; as the parasite matures the membrane 

 becomes thinner and the striations disappear, until, in the largest forms as seen in 

 cattle, the parasite appears to be held only by the sarcolemma of the muscle fibre. 

 Evidently the parasites are able to multiply within the body of their host until every 

 part of the muscular system is invaded; this endogenous mode of infection 

 is hypothetically brought about by rupture of the cysts and dissemination of the 

 spores, and yet, if this is actually the case it is strange that even in such severely 

 infected cases as I. and II., no intermediate forms between the relatively minute 

 spore and large young trophozoite could be found. 



The spores themselves, the clamydospores, vary considerably in shape, size, and 



