SARCOSl'ORIDIA. 211 



against it. Bieuil and Behrens showed that a sokitioii of normal 

 sahne of Sarcosporidia of a llama inoculated into rabbits gave 

 rise to symptoms referable to the nervous system — -ascending 

 paralysis, subnormal temperature. There was no diarrhrea. 



McGowan, in his investigations, made several observations 

 on the effect of injections into rabbits of extracts of muscles 

 from scrapie sheep. These extracts were found to contain a 

 toxic substance similar to that described above, and derived from 

 the Sarcosporidia present in the muscles. The toxic action of 

 the extract was found experimentally into rabbits to depend on 

 the number of sarcocysts present in the muscle. Corresponding 

 extracts from the muscle of normal sheep (without sarcocysts) 

 had no toxic effect. The action of the toxin was chiefly tested 

 C)n rabbits. 



How ARE THE Sarcosporidia Spread? 



Investigators tried to transmit the disease by feeding various 

 animals with sarcosporidial flesh. This was based on a possible 

 analogy of the disease with trichinosis. The first exj^eriments 

 which threw some light on the subject were performed by Theo- 

 bald Smith in igoi. He succeeded in infecting grey mice by 

 causing them to eat the bodies of some of their fellows which had 

 died of sarcosporidiosia. He judged that he had artificially in- 

 fected the mice by the fact that the percentage of infected mice was 

 much larger than among the stock mice. He thinks that the 

 method of infection is direct, and that there is no intermediate 

 host, such as biting insects, etc. Koch and Negri confirmed 

 Smith's observations, and the latter found that young mice were 

 nnich more easil}^ infected than old ones. He further states 

 that the faeces of mice that have eaten sarcosporidial flesh are 

 capable of infecting healthy mice from the fifteen'th to the 

 fiftieth day after infection. These faeces remain effective if 

 kept dry for a month, or if heated for 15 minutes at 65° C, but 

 lose it if they are heated at 85 '^^ C to go° C. for a similar period. 

 Negri fed white rats and guinea-pigs on the mouse sarcospo- 

 ridium and produced the disease in them. Erdmann produced 

 infection in mice by feeding them on the sarcocyst of the sheep. 

 V. Betegh and Dorich fed two ducks and a fowl on cysts from 

 the oesophagus of a sheep and produced an infection. Kasparek 

 injected a mouse subcutaneously with the contents of a sarco- 

 spordial cyst from the oesophagus of the sheep. It died in 

 24 hours, and on examination of the heart blood, he states that 

 he found bodies resembling sporozoites. Pfeiff'er had per- 

 formed a somewhat similar experiment with a somewhat similar 

 result, and suggested the possibility of a blood-sucking inter- 

 mediate host. Minchin attributes to Watson the statement 

 that sporozoites are to be found in the circulating blood, and 

 draws attention to the possibility of this indicating the trans- 

 mission by an intermediate host. As pointed out above, spo- 

 rozoites have often been seen in the blood smears from cattle 

 in South Africa, yet, accepting Sarcosporidia to be the cause of 

 lainsiekte, all transfusion experiments have failed to set up the 



