SPAWNING. 31 



separate vessel of water and mixed with the eggs. A 

 hatch of sixty per cent, was thought very good in 

 those days, and so undoubtedly it was, if the result be 

 regarded by the light of our modern knowledge. The 

 thing would seem to be almost impossible, but for one 

 fact lately made public by Mr. Jackson, of the South- 

 port Aquarium, whose microscopic investigations of 

 the movements of milt in water are very important. 

 He tells us that when milt finds itself in water the 

 spermatozoa distribute themselves throughout it, each 

 keeping an equal distance from the other, so as to 

 miss nothing. In fact, he compares the appearance 

 of these objects, seen in the field of a microscope, 

 with the patterns of shot, as advertised by makers of 

 close-shooting guns ; but points out that the regularity 

 of the distance of the spermatozoa from each other was 

 almost, if not quite, invariably observed, each one 

 maintaining its position relatively to the rest, as the 

 milt spread through the water. This is a matter of 

 the greatest importance, and should receive further 

 attention, as it leads us to a clearer comprehension of 

 the manner in which eggs are naturally fertilized in a 

 stream, and cannot fail to be of great interest to the 

 student of physiology, 



We have said that under the old regime sixty per 

 cent, was thought good. By degrees, however, less 

 water was employed, and the result was found to 

 justify the innovation ; so that gradually one vessel 

 was substituted for two, and very little water was used. 

 The veteran pioneer in pisciculture, Seth Green, found 

 this out many years ago, as Mr. Stone tells us in 

 Domesticated Trout ; and, though ready to impart 

 any other fact to others, he carefully kept this to 



