336 Dr. E. Strasburger on Fertilization in Ferns. 



sphere, and dissolved away in its mass till, at the expiration 

 of three or four minutes, no more could be seen of it. This 

 operation was only witnessed five times out of numerous ex- 

 periments, and when a single spermatozoid alone had pene- 

 trated into the central cell, owing to the canal being occupied 

 by adventitious matters. When several spermatozoids had 

 reached the central cell, they moved about amongst each other, 

 so that it was impossible to follow any individual. Sometimes 

 two or three of these bodies remained with their hinder ends 

 attached to the germ-spot ; they turned quickly on their axis, 

 pushing one another aside, till one gained the mastery, and 

 was so far received that it covered up the germ-spot with its 

 coils. The others Avere then repulsed, and moved about for 

 some time, their motions ceasing at times, to be recommenced 

 after short intervals ; this may have lasted eight or ten minutes, 

 when they all sank to rest, and remained motionless where 

 they fell. In one case, when two spermatozoids had reached 

 the central cell, the second approached after the first had occu- 

 pied the germ-spot a minute and a half and its front coils had 

 been received into the germ-sphere; the second could not then 

 displace the other, but soon relinquished its hold on the germ- 

 spot, and, after long roving about, lay on its side near the 

 germ -sphere. After four minutes nothing more was seen of 

 the first ; and after thirty-five minutes the second was also lost 

 sight of. The usual results of the fertilization followed in the 

 growth and colouring of the embryo, and were very conspi- 

 cuous after the lapse of a few days. 



Dr. Strasburger concludes his account by observing that 

 fertilization seemed to be effected in these instances by a single 

 spermatozoid, and considers it probable that the procedure is 

 similar in the other Cryptogams which produce these bodies. 

 The chief point of interest in the above experiments (which 

 the author appears to have carried further, and to have detailed 

 with greater accuracy, than previous observers) consists in the 

 means adopted by nature to conduct the spermatozoids to the 

 scene of their operations, and in his reasonings on the nature 

 of their movement, which has been sometimes supposed to be 

 connected with molecular motion by those who have not ob- 

 served it with sufficient care. It remains for future inves- 

 tigators to ascertain if the same facts can be traced in other 

 Cryptogams. 



