SPERMATIC PARTICLES. 43 



curled around. Nevertheless, this may be considered only an accidental relation, the 

 particle, most probably, having no relation with the parietes. 



I have always noticed that in these cases the nucleus is absent, and this fact has led 

 me to adopt the view, that it is transformed directly into the particle, the cell-membrane 

 acting simply as a protecting shield for the process. This view would involve no new 

 or anomalous morphological process, if we consider the real nature of the nucleus, and 

 its relation to the parent cell ; namely, that it differs not at all from the cell, except in 

 being the active metamorphosing agent.* 



Both Kolliker and Wagner have inclined to the opinion, that this form was developed 

 on the inside of the cell by aggregated particles, exactly as lignine is deposited on the 

 inner surface of vegetable cells of woody plants. This is quite plausible, but the fact, 

 that I have seen among the higher Mammalia the sperm-vesicles undoubtedly filled 

 previously with segmented cells, having, on their inner side, particles, and these gen- 

 erally four and eight in number, would seem to show that they were formed either 

 from or in segmented cells, and became there situated afterwards. 



The tail of the spermatic particle, from its constant presence, has most probably 

 an inappreciable importance. 



As to their genesis, I do not think it referrible to exactly the same processes as 

 those of the body proper. It appears to be a subsequent formation, and not formed from 

 either the cell or the nucleus, but rather from a minute granular matter. 



The parietes of the parent vesicle of most of the spermatic particles of Mammalia 

 have a delicacy amounting almost to real transparency. It is difficult to conceive of 

 an organized structure having a fineness more delicate than this ; and yet the very 

 spermatic particles formed within have tails far more delicate than this membrane 

 as to thickness. 



Among the osseous fishes, the tail has a still greater delicacy of structure, and it 

 would be very absurd to suppose that these are formed from a cell-membrane, since 

 this last is formed of layers of granules, each of which very granules has a diameter 

 equal with the tail itself, and perhaps larger. IMoreover, it not unfrequently occurs, 

 that, within the field you are viewing, there are some bodies with no tails. And 

 I have noticed, that, during the unprocreative season among the lower classes, a few 

 spermatic particles are formed, but they are generally deficient as to tails. This may 

 easily be seen with some of the common Batrachians. 



These two facts, and another, that these bodies generally lose their tails with their 



* Vid. Transactions of the American Association for the Advancement of Science, 1849, p. 261. 



