164 PARASITES OP MAN 



that the larval Trichinae were the cause of death. The intes- 

 tinal canal contained numerous sexually-mature worms. 



The effects produced by Trichinae on animals are similar to 

 those occasioned in man. The phenomena were summarised 

 by Davaine (in the journals quoted below) in 1863 as follows : 



" The first phase is characterised by intestinal disorder, pro- 

 duced by the development of the larvae in large numbers, and 

 their adhesion to the mucous membrane of the intestine. In 

 this stage M. Davaine has seen rabbits die with intense diar- 

 rhoea ; one of two cats which he fed with trichinised meat had 

 diarrhoea for at least a fortnight, but survived. Of five or six 

 rats fed on a similar diet, one only, which was pregnant, died 

 of diarrhoea, after abortion, on the eighth day. According to 

 M. Leuckart, the passage of the embryos of Trichinae through 

 the intestinal walls sometimes produces peritonitis. This intes- 

 tinal phase often becomes blended with the next ; it may be 

 relieved by the expulsion of the worms by means of the diar- 

 rhoea, or may cease with the natural death of the worms. 



" The second stage presents general symptoms muscular 

 pains, &c. These phenomena are dependent on the introduc- 

 tion of the Trichinae into the muscles; they rapidly acquire 

 their maximum intensity, and have not a long duration. The 

 appearance and duration of this stage are in complete relation 

 with the development and length of sojourn of the Trichinae in 

 the intestines ; in fact, in this entozoon, oviposition is not slow*" 

 and of long duration, as in many nematoid worms ; the genital 

 tube is rapidly formed, and the ova, in its whole length, are 

 developed almost simultaneously, so that the embryos, arriving 

 soon at maturity, are at once thrown out in large numbers into 

 the intestine, and the mother Trichina dies exhausted. If it 

 be remembered that the embryos do not escape before the 

 eighth day, that a certain number of days are required for their 

 arrival in the muscles, and that new ones are not produced 

 after six or seven weeks, it will be understood 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 dis- 

 appear. 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. 



