10 Fishery Board for Scoiland. 



Milt and Spairn. 



Some milt from a dead herring was put into sea-water. I found the 

 sperms (fig. 7) oscillating vigorousl_y as if anchored by the tail. 

 Many, however, oscillated very faintly. 



No difference was observed between the spawn of the living and 

 dead herrings. 



Some unfertilized eggs, a quarter of an hour after they had been 

 deposited on the glass plate, exhibited different shapes (fig. 8). Most 

 of them show an inpushing where they had been pressed by another 

 egg. No sign of perivitelline space was visible^ The eggs were 

 easily dislodged from the glass. They do not adhere strongly until the 

 perivitelline space is formed. Three days later these unfertilized eggs 

 had a fairly large perivitelline space, but they remained dull tinted on 

 the outside, instead of showing a clear translucent zona. 



Thk Ceyrtals in the Eggs. 



The crystals, which were very evident during the two previous 

 experiments, were found also on this occasion. They are rectangular 

 (fig. 5), sometimes ending in a tapering oblique point. They may be 

 fine, needle-like, or fairly thick bars. They appeared in the batches 

 of eggs which were exposed to the influence of galvanized iron. In 

 one instance, they appeared within 36 hours after fertilization (fig. 10\ 

 This egg had been in still water in an enamelled bath for a night, and 

 had probably with it some galvanized gauze. 



No crystals were observed in the uncooled eggs on gravel. The 

 water was delivered to, these eggs through large galvanized iron pipes, 

 which had been in use for several years. All the cooled spawn 

 received water through a series of small galvanized iron pipes. 



One remarkable fact is that the crystals were not present in all the 

 eggs of a batch. They may be found (1) on the inside of the zona; 

 (2) between the layers of the zona ; (3) attached to the yolk or to the 

 embryo ; and (4) within the embryo. 



These crystals are soluble in acetic acid, and in sodium hydrate 

 solution. Thej^ are insoluble in water, alcohol, and methylic ether. 

 Dr. J. K. Wood, Chemical Department, University College, Dundee, 

 says that the crj^stals, being able to act both as a base and an acid, are 

 probably formed from proteids by some process of decomposition. 



I have came to regard the galvanized iron as, in some measure, the 

 cause of the formation of these crystals. The galvanized iron becomes 

 coated with a white incrustation in sea-water. Dr. Wood was not 

 able to find zinc in solution in the sea-water in ^^'hich a piece of this 

 metal had been lying for several days. It seems possible that the 

 cause of the formation of the crystals is to be found in electrolytic 

 action. The electric current acting within the eggs on the fluids con- 

 taining exci'etor}^ products causes the crystallization. I formerly 

 regarded the crystals as indicative of deficient aeration, and I still 

 favour that view. The deficient aeration resulting in the accumulation 

 of excretory products in the perivitelline fluid may afibrd the oppor- 

 tunity for the action of the current. All the eggs do not exhibit the 

 crystals. It is possible that the zona may not be acting satisfactorily 

 from the point of view of osmosis. It is possible that variation may 



