210 SARCC^Si'OKIDIA. 



on the concave side of the sickle, which is hlled with a material 

 c.ontainin<i;- no oranules, at least until the bulge becomes very 

 large. The bulge gets larger, the nuclear s])ot becomes indis- 

 tinguishable, the sickle swells, the granules appear to multiply 

 and get larger, and the ]jrotoplasm becomes very \'acuolated, 

 and the concavity of the sickle a])])ears in the opposite direction, 

 until hnally a rounded form is reached. The cyst then bursts, 

 giving rise to an empty round sheath and a mass of vacuolated 

 material containing a large niunber of granules. This latter 

 mass disintegrates into free granules and debris. These granules, 

 according to McGowan, a])])ear to be the final develo])ment of 

 the sickle, \vhich produces new infections. 



Sarcocystine. 



Pfeift'er found that an ac(ueuous extract of Sarcosporidia, 

 inoculated beneath the skin of a rabbit, led to a fall in tempera- 

 ture, diarrhoea, and ultimately death of the animal. Laveran 

 and Mesnil repeated the above, and proved the existence in the 

 Sarcosporidia of the sheep of a toxin to which they gave the 

 name sarcocystine. They prepared both aqueous and glycerine 

 extracts. The toxin is pre]:)ared by enucleating a nimiber of 

 cysts, v^eighing them, and crushing them in a mortar with sterile 

 sand and a known volume of water and glycerine. Filter the 

 aqueous extract through a porcelain bougie, and the glycerine 

 extract through paper. They, moreover, prepared a highly 

 toxic dry extract. A number of cysts are dried in a desiccator 

 over HvSO^ and powdered ; the white powder constitutes the 

 extract, and must be stored in small sealed tubes. 



The properties of sarcocystine resemble those of certain 

 bacterial toxins and venims. The aqueous extract was found 

 to lose its toxicity rapidly, so that in six days it was already 

 much less toxic than when prepared ; the glycerine extract, on 

 the other hand, which is quite as toxic as the aqueous extract, 

 keeps nmch better, and preserves its toxicity unaltered for about 

 a month. The aqueous extract, moreover, loses its toxin, when 

 heated to ioo° C. for five minutes, or at 85° C. for 20 minutes. 

 The glycerine extract is more resistant to the action of heat ; 

 after heating to 85° C- for 30 minutes, it will still ])rove fatal 

 to rabbits if inoculated in large doses. The toxicity of the 

 extract is not diminished by triturating it with rabbits' brain 

 or muscles, so that the toxin is not fixed by these tissues. 



Sarcocystine, as far as is known, is very toxic for rabbits, 

 and almost without effect on other animals. Guinea-pigs, rats, 

 mice, and sheep are much less susceptible, as are also frogs and 

 tortoises. A dog, a hen, and a pigeon lost weight after injection. 

 The toxicity in the rabbit half a milligramme of sarcocystine 

 killing one kilogramme of rabbit. However, in the literature 

 very varying accounts are given on the susceptibility of various 

 species of animals to sarcocystine. 



Teichman and Braun hold that sarcocystine is thermolabile, 

 filtrable, and soluble in salt solution, and rabbits can be immunised 



