American Fisheries Society. 89 



It is vcrv simpk' and l)y ihc perusal nf any one of the many 

 good books of instruction on the use of the instrument, and a 

 little jiractice, its mastery will come to you witli surprising rajv 

 iditv, and \t»ur interest will goad you on until y(ju will find your 

 back and eyes aching, and glancing at your watch, you will 

 dash ofT for your dinner, conning over some good story on the 

 way to tell your wife as to what made you late. 



The most important work CJf the microscope in practical fish 

 culture is, doubtless, to determine the condition of eggs soon 

 after they are taken so as to remedy early any errors of the spawn- 

 laker which may exist and thus save unnecessary loss. 



In examining eggs under the microscope I use a cell that 

 liolds about a certain number of eggs, as for instance, in the case 

 of the whitefish my cell holds twenty eggs in a row and five rows 

 deep, making in round numbers lOO eggs, although eggs vary 

 so much in size that this is not absolute. 



In making an examination the eggs which are impregnated, 

 unimpregnated and those with ruptured yelks arc so easily de- 

 tected, one from the other, that the cell may be moved under the 

 microscope as fast as you can count. 



It is the practice of the writer to examine whitefish and cisco 

 eggs twenty-four hours after they are taken, when segmentation 

 is at its most distinct period. The disc of the impregnated q^^ 

 will then be found divided into some fifteen or twenty cells, nicely 

 rounded into nodules looking under a half-inch objective as large 

 as kernels of corn. The disp of the unimpregnated egg will l)e 

 an almost perfect hemisphere and will present a much clearer 

 appearance than the impregnated one. The eggs with ruptured 

 yelks will present a varied appearance. Generally the albumen 

 will be in a layer at the bottom, the oil globules at the top and the 

 disc, much distorted and out of all semblance of the normal, float- 

 ing between the two. There is another class of valueless eggs, 

 those containing no germinal disc at all, but they constitute a 

 very small per cent., and as, of course, no amount of care on the 

 part of the spawn-taker could put life into these, they need not 

 be taken into account at all. 



Thus it will be seen, the eggs at the station can be examined 

 each day, each lot separately, and a record of the work of each 

 and every spawn-taker kept, his errors corrected or the man dis- 

 charged, and by going over your tables resulting from this work, 

 when you are about to engage your spawn-takers for a season. 

 Jyou can see at a glance who are your best men, weed out the 

 poorer ones and greatly improve your spawn-taking force. Of 



