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On the Mature Condition of Trichina spiralis. By 

 Dr. Rudolph Leuckart. 



Some months since I communicated to my friend, Professor 

 Van Beneden, at Louvain, the results of a helminthological 

 experiment , which appeared to establish the connexion of 

 Trichina with Trichocephalus, already supposed to exist by 

 Meissner, Kiichenmeister, and others. In this experiment, 

 I fed a young pig with a quantity of trichinised flesh, for 

 which I had been indebted to the kindness of Professor 

 Nasse of Marburg ; and on dissection, after the lapse of four 

 weeks, I discovered in the large intestine a very considerable 

 number of Trichocephalus dispar, probably thirty or forty 

 specimens, some of which were in a state of perfect sexual 

 maturity, and some nearly in that condition. 



Professor Van Beneden communicated the result of this 

 experiment to M. Milne-Edwards, who regarded it of such 

 importance that he considered it worthy of a brief notice 

 before the Academy of Sciences in Paris. 



Shortly afterwards a letter from Professor Virchow was 

 read in the same place, in which it was stated that in the 

 intestine of a dog fed with flesh containing Trichina, at the 

 end of four days a vast number of minute free vermiculi were 

 found, which were manifestly sexually mature Trichina, or 

 which, at any rate, were in a condition approaching matu- 

 rity. With respect to the ultimate destiny of these vermi- 

 culi the observer remained in doubt, not regarding it as 

 altogether impossible that they might become Trichocephali ; 

 he was, however, more inclined to assume that they had some 

 relation to Strongylus. 



I must confess that on reading this letter I suspected some 

 error on Virchow's part, chiefly because, according to all ex- 

 isting experience, it appeared incredible that a previously 

 asexual worm (for such is the Trichina, although already pre- 

 senting the rudiments of a sexual organ) should, so early as 

 on the fourth day after importation, " be found to contain 

 fully developed ova." 



But I must hasten to retract this supposition of error, as 

 totally unfounded. 



According to my present researches, there can be no doubt 

 that Virchow is perfectly right. Trichina spiralis, in the 

 intestine of the dog, assumes, in a very short time, the con- 

 dition of sexual maturity, but independently of a previous 

 transformation into any already known form qf thread worm. 



A short time since I obtained from Professor AVclcker, of 



