504 



SEMEN. 



to cause the whole fibre to be moved round 

 in a circle. 



The normal movements of the spermatozoa 

 just described must be distinguished from 

 various other remarkable and irregular pheno- 

 mena of motion which are perceived on treat- 

 ing them with water, particularly in the long 

 and hair-like spermatozoa of the Insects, Gas- 

 teropoda, Helmintha, and Cirripeda, and also 

 sometimes, although in a slighter degree, in 

 those of the Reptilia and Mammalia. Siebold* 

 was the first who estimated these latter phe- 

 nomena at their proper value, attributing to 

 them their real cause, viz. the hygroscopic 

 quality of the spermatozoa. 



These phenomena take place only on the 

 addition of fresh water, whilst sea water 

 exercises but little influence on the sper- 

 matozoa, which may be accounted for by 

 the difference in the saline constituents of 

 these fluids. This fact, however, is of the 

 greatest importance, in a physiological point 

 of view, because the fecundation of the ova 

 in many marine animals does not take place 

 by copulation, but is accomplished through 

 the transfer of the spermatozoa by means of 

 the sea water, and the influence of this me- 

 dium should not be such as to destroy the 

 power of motion on the part of the sperma- 

 tozoa. In cases where the fecundation takes 

 place in the same manner in fresh water, for 

 instance in the muscles, the spermatozoa are 

 but slightly hygroscopic, so that their in- 

 tegrity remains undisturbed. 



These abnormal phenomena of motion, 

 caused by the influence of water, exhibit 

 something similar to that which is seen in a 

 rope turned by a wheel in a rope yard. The 

 spermatozoa roll themselves out in larger or 

 smaller windings, and form simple or com- 

 pound coils of the most variable kinds. Fre- 

 quently they turn back again after some time, 

 and re-assume their original shape ; they fre- 

 quently also remain in the position they have 

 at first assumed. In short, changes take place 

 every moment. When the fibres lie in a 

 straight position, a number of coils are sud- 

 denly produced; but they disappear equally as 

 quickly, and it is only after some hours, when 

 all the spermatozoa have rolled themselves 

 into these coils, that the movements finally 

 cease. 



It is interesting that the normal undulating 

 motions of the spermatozoa, where they lie 

 together in regular masses without being able 

 to change their position, very frequently 

 coincide in a remarkable manner, appearing 

 to be carried out, as it were, by one common 

 will. But although this may appear strange 

 at the first glance, it cannot surprise us when 

 we consider that the same behaviour is ob~ 

 served in the ciliated cells. We here see the 

 motions in the cilia of one epithelium regu- 

 lated, as it were, by one common plan ; we 

 observe how these coincide with the move- 

 ments of the cilia of others, and thus unite 

 into one regular motion of the whole. A 



* Miiller's Archiv. 1836, S. 19. 



peculiarly beautiful sight is afforded by the 

 aggregate motion of the spermatozoa in the 

 semen of the earth worm, which resembles the 

 undulating motion of a corn field. Among the 

 insects we have also various opportunities of 

 observing this kind of aggregate motion. 



A similar aggregate motion is frequently 

 (especially among the Invertebrata) found in 

 the separate bundles of spermatozoa, even 

 when they are still surrounded by their cyst- 

 like enclosures. At first sight it creates 

 an impression as if an undulating fluid were 

 agitated in the interior of the cysts, whilst it 

 is merely the winding motions of the sperma- 

 tozoa, which follow each other in quick and 

 regular succession, imparting the impulse to 

 the whole mass. 



Motion, however, is entirely wanting when 

 (as is especially the case among the insects) 

 the spermatozoa are united into simple and 

 uniform cords. A slight curving or trembling 

 is only observed now and then, which is 

 evidently the consequence of hygroscopic 

 conditions. 



We know as little of the cause of the 

 movements of the spermatozoa as we do, in 

 point of fact, of the remote cause of every mo- 

 tion. But that it depends on certain relations of 

 structure and composition, is evident from the 

 circumstance, that it is wanting in the unde- 

 veloped spermatozoa, only gradually taking 

 place with progressive developement. A slight 

 vibration or beating with the tail is first of all 

 observed in them. The most lively, most 

 vigorous, and most combined motion takes 

 place, on the other hand, during the period of 

 rutting, when the developement of the fructi- 

 fying spermatic elements has reached its 

 height. 



But the motion of the spermatozoa is not 

 even then unlimited. The death of' the ani- 

 mal in whose spermatic organs they are con- 

 tained, or their removal from it, only allows 

 the motions of the spermatozoa to survive for 

 a time, which, however, is of a different dura- 

 tion in different animals. It seems to be 

 shortest in the birds, where the motion fre- 

 quently is extinguished fifteen or twenty mi- 

 nutes after death ; at least it can but rarely 

 be observed after some hours. In the mam- 

 malia their motion survives some time longer, 

 especially if they remain enclosed in their 

 natural organs. 



Death, or removal, seems to have a different 

 influence on the spermatozoa of the cold- 

 blooded animals ; among the fishes, for in- 

 stance, they continue moving for days after 

 having been expelled from the body. The 

 mode of death of the animals has no influence 

 at all upon the duration of the motion in the 

 spermatozoa. It remains all the same whe- 

 ther the animals are decapitated, strangled, or 

 poisoned. 



The motion of the spermatozoa survives 

 longest of all in the interior of the female 

 generative organs. The insects (in whom, as 

 in Gasteropoda and some other animals, parti- 

 cular pockets or capsular organs are deve- 

 loped during the period of procreation) furnish 



