TEICHINA SPIRALIS. 349 



But how these encysted nematode worms, with our present 

 state of civilisation, can reach, before the period of their death — 

 which, however, only occurs very late, perhaps in 30 — 40 years, 

 or after a still longer period in particular cases — places in which 

 they are in a position to pass through their further and higher 

 development, is beyond my power to divine. Even the adminis- 

 tration of these Trichina to dogs gave no result, either in the 

 experiments made by me or those made elsewhere ; in about six 

 weeks I found nothing of Entozoa which resembled the Trichinae. 

 In my experiments I certainly made two great mistakes. In 

 the first place I fed the dog with muscle in a state of incipient 

 putrefaction ; instead of which it would have been more judicious 

 to have scraped off the individual capsules of the Trichinae, and 

 perhaps, in order to facilitate the escape of the worm, to have cut 

 them at one end. As visual in dogs confined in a room, a 

 brisk diarrhoea took place in this case after the administration. 

 I fell into a second error by not examining the csecum and 

 large intestine of the dog with sufficient care. To avoid this 

 error, I advise future experimenters to soften the excrement of 

 the large intestine of the animal employed in the experiment in 

 lukewarm water, and pass it through a fine cloth or hair sieve, 

 by which means they will more easily find the worms, and none 

 of them will be lost. 



The experiments of Zenker and Leuckart terminated as un- 

 successfully as my own. The latter had the kindness to inform 

 me with regard to his experiments that he sought in vain in the 

 intestine of rabbits, cats, and dogs for Ascarides which might 

 have been produced from the Trichinae administered. In the 

 intestinal mucus of mice, however, he found young Trichinae two 

 days after administration, and Trichinae might perhaps be dis- 

 covered in the intestinal mucus of other animals. All further 

 expectations, however, unfortunately remained unfulfilled, as the 

 three other mice experimented on had acquired an appetite for 

 flesh by the administration, bitten each other on the third da}^, 

 and were thus destroyed on the fourth. This latter fact is not 

 isolated, for my colony of white mice also killed each other by 

 gnawing, which manoeuvre commenced from the time when I 

 had fed them with fat pieces of Taenia crassicollis. In experi- 

 ments of this kind wc must, therefore, keep the mice separate. 

 However, none of us found Trichinae in the muscles of the 



