350 ENTOZOA. 



of days are required for tlieir arrival in tlie muscles, and that new 

 ones are not produced after six or seven weeks, it will be under- 

 stood that the first symptoms of this stage can scarcely appear 

 until the end of a fortnight after ingestion of the diseased food, 

 that they must continue four or five weeks, and that after this 

 they may disappear. This course of events is observed in animals ; 

 and in man, the symptoms of this stage have shown themselves and 

 become aggravated from the third to the sixth week after infection. 

 Most animals die during this stage ; rabbits rarely survive ; rats, 

 on the contrary, generally resist it. 



" If the animals do not die of the general symptoms or local 

 disturbances proper to these two stages, the inflammatory symp- 

 toms cease, respiration becomes natural, and order is re-established. 

 But, in some cases, the number of cysts formed iil the muscles are 

 su0B.ciently great to impede them in the proper exercise of their 

 functions, and hence arises general debility, a kind of consumption 

 which persists or becomes aggravated, and the animal dies of 

 marasmus. M. Davaine has noticed this in rabbits, but especially 

 in a rat. 



" Recovery fi:'om these phases of trichinal infection may be 

 apparently perfect. A rabbit, which M. Davaine kept during five 

 months, became large and fat, although it had a large number of 

 Trichinse in its muscles ; a rat which had had these Entozoa in con- 

 siderable numbers during six months, was, to all appearance, in 

 good health. Hence he concludes that the TrichinsB produce symp- 

 toms only when they are in the intestinal canal, and when they are 

 entering the muscles. Having become lodged in their cysts among 

 the muscular fibres, they may remain harmless for an indefinite 

 time. In every case except one, down to 1859, Trichinae have been 

 found in the bodies of persons who have died of disease (generally 

 chronic) or by accident; or in the dissecting-room, in bodies 

 regarding which the previous history could not be obtained. In 

 most cases, the cysts contained a cretaceous or fatty deposit, 

 showing that they had probably existed several years. 



