M. Treviranus on the Organized Bodies in 



These inmates of the fructifying animal secretion have been 

 for a considerable time the subject of my observations. I have 

 alre{,dy made known in some of my earlier publications, two 

 of the results obtained by my investigations : the accuracy of 

 these results I have repeatedly tested within the last few years, 

 whenever I had an opportunity of procuring fresh semen from 

 animals recently killed, and I have found them verified in every 

 instance. One of these is, that the motions of these bodies occur 

 either solely in the seminal fluid of animals in heat; or that 

 they are observed to be much more lively during the period of 

 heat than at any other time. The physiologist may easily sa- 

 tisfy himself as to the truth of this assertion, by examining 

 the semen of moles, frogs, and fishes, during the season of co- 

 pulation, and beyond that period. During the former, the se- 

 men is full of organized parts, which exhibit a lively motion 

 through each other. After the period of copulation is over, 

 we cannot discover any vital movement. In moles, whose tes- 

 ticles and seminal vesicles I examined about the last days of 

 July, I could not discover any semen ; and the few drops of 

 fluid which I obtained from those parts, exhibited no trace of 

 seminal animalcules, or of motion. Many similar observations 

 had been previously made by Buffon, Daubenton, and Need- 

 ham, without attempting to draw from this fact the deductions 

 which it affords. From being unacquainted with, or from not 

 having observed this influence of heat on the constitution of 

 semen, physiologists have occasionally denied the existence of 

 seminal animalcules in the semen" of many animals ; in which, 

 however, they are undoubtedly present during the season of 

 heat. Thus, Prevost and Dumas state, in one of their earlier 

 essays, that these animals are not contained in the seminal fluid 

 of fishes. In a later publication, M. Prevost mentions that he 

 had found them in the semen of the Mullus gobio, but does 

 not give any explanation as to the cause of the discrepance be- 

 tween this and his former experiments; a discrepance which 

 can only be attributed to the difference of the seasons at which 

 he made the seminal fluid the subject of his observations. 

 I examined the semen of various insects during many sum- 

 mers, without finding in it, except very rarely, any parts exhi- 

 biting traces of motion. As my examinations had been made 



