12 THE DISEASES OF DOMESTIC ANIMALS. 



d. Professor Dammau,* formerly of the Eldena Agricultural 

 Academy, reports a very interesting case, illustrating the longevity 

 and tenacity of life of embryonal trichinae in the muscles of a hog. 



This hog was fed with trichinous meat in November, 1864, and 

 in February, 1865, presented to the experiment station at Eldena. 

 Since that time the animal had been kept isolated, unless removed 

 from its pen for examination. On February 3, 1875, and February 

 12, 1876, Dammau removed a small piece of flesh from the shoulder. 

 At both times trichinae were found. A considerable piece of flesh 

 was removed and fed to two rabbits, and eighteen days subse- 

 quently their muscles were found to be plentifully invaded with 

 trichinae. 



This case demonstrates, beyond all question, the presence of 

 living trichinae, which were capable of maturing, fructifying, and 

 developing young when fed to other animals, after a period of 

 eleven years and a quarter from the time that the invasion of the 

 hog took place. 



Although the encapsulated trichinae suffer no changes while 

 confined in the muscles of an autositic organism, yet the introduc- 

 tion of portions of such muscles into the intestinal tract of man, or 

 other suitable animal, causes rapid changes in their condition. The 

 processes of digestion soon set the imprisoned parasites free from 

 their capsules, three to four hours being sufficient for the purpose. 

 The freed parasites rapidly complete their development to mature 

 trichinae, thirty to forty hours being enough. In cases of fresh in- 

 vasion, when the capsules have not become very hardened, twenty- 

 four hours have been found sufficient to demonstrate the presence 

 of sexually matured trichinae in the intestines of animals fed with 

 such flesh by way of experiment. Still, we may often find trichinae 

 inclosed in their capsules on the third day after feeding infected 

 flesh to an animal. 



There is scarcely another helminth by which this matured stage 

 in its development is reached in so short a period. 



Under these circumstances it is self-evident that the changes 

 necessary to maturity by these parasites must be of a very insignifi- 

 cant character. 



As a rule, sexual connection takes place within two days from 

 the time the trichinae become free. 



The parasite increases in length and thickness, and in the fe- 

 male the uterus fills with fructified ova, which soon develop into 

 embrvos still inclosed in the maternal worm. 



* "Zeitschrift fur prac. Thierheilkunde," 1876, vol. iii, p. 92. 



