[7] ARTIFICIAL PROPAGATION OF OYSTERS. 747 



off, and the sediment at the bottom throu-n away. There is no other 

 way of satisfixctorily getting rid of the fragments of the various organs. 

 I have strained the fluids through fine muslin, have squeezed them out 

 of the generative organs with the hand instead of cutting them up, 

 have even ground up the visceral mass in a coffee-mill; but I found 

 no method so productive of good results as obtained by chopping 

 the reproductive organs into a few pieces and washing tliem once or 

 twice in a glass of salt water, allowing the glass to stand a few minutes 

 and then pouring off the water containing the eggs and excess of male 

 fluid. 



After getting rid of the debris, the contents of the glass should be 

 stirred frequently for ten or fifteen minutes and then allowed to stand 

 quiet that the heavy, fertilized eggs may sink to the bottom. Only one 

 precaution is here necessary; too many eggs must not be collected in 

 one glass. The layer on the bottom should not exceed one-eighth of 

 an inch in thickness, and a smaller number of eggs is preferable. 1 

 succeeded better when I used a large number of small glasses (tumblers) 

 than when I used one or two large jars (trout hatching jars) for this 

 part of the process, and not only were the results better but there was 

 an appreciable saving in time, with the tumblers. The evils of the large 

 receptacle are the same as those noticed when too many eggs were put 

 in one tumbler. So much time was taken up by the eggs in sinking to 

 the bottom after each renewal of the water, that spermatozoa were car- 

 ried along with them, and the eggs after reaching the bottom were 

 packed so closely together, and on top of each other, that they resem- 

 bled a slimy mass of mucous, and could not be readily detached from 

 the glass or from one another. Such conditions obviously hinder de- 

 velopment and should be guarded against. 



The removal of the excess of male cells and unripe or floating eggs 

 is a simple matter of easy accomplishment. As soon as the eggs are 

 at the bottom of the glass, siphon off the water and refill the tumbler. 

 After the first two or three operations the eggs can be seen as a white 

 cloud sinking through the water ; ten minutes rest between the oper- 

 ations is quite suificient time for the eggs to sink. If they do not 

 descend in a solid mass, but " straggle" to the bottom, it is an indica- 

 tion that there are many but partially ripe or unimiiregnated eggs in the 

 lot and that the prospect of a successtul issue to the experiment is 

 slight. The water should be changed until, after the eggs have sunk 

 to the bottom, it is perfectly clear. The investigator can then pro- 

 ceed to the next operation. 



3. Care of the eggs during segmentation. — After the water in the glasses 

 has been cleared, and all deleterious matter disposed of, it is of greatest 

 imi)ortance that the eggs should have room for development; that is 

 thatthe^' should not press upon or in other ways incommode each other. 

 There are a number of other points of importance to be observed but 

 1 defer their consideration, for the present confining myself to features 

 of the manipulation that must be common to all exijeriments. 



