INCUBATION 93 



difficulty in obtaining them of late, have been 

 in the habit of preparing them ourselves by slight- 

 ly warming a common tallow dip and dusting 

 strychnine over the surface. The advantage of 

 applying it in this manner is that candles are not 

 affected as food by either human beings or domes- 

 tic animals, and that thus the danger always to 

 be dreaded when using virulent poisons is almost 

 entirely avoided. If, on examining the trays, the 

 spawn which was left neatly arranged decently 

 and in order upon the grilles, is found heaped or 

 disturbed, the presence of rats or mice may be 

 suspected. 



The study of the development of the fish in the 

 egg, from the first day of incubation to the emerg- 

 ence of the young fish, is one of great interest, 

 though in our own country but little has been 

 done in this direction, few to whom the opportu- 

 nity is given having the time, patience, or scientific 

 knowledge necessary. The work of Mr. Yogt * 

 contains all that is known upon the subject, and 

 to this we must refer the scientific fish culturist, 

 confining ourselves only to those changes which 

 appear to the naked eye, or beneath the power of 

 an ordinary lens of from one to two inches focus. 

 For examination the eggs should be placed in a 



* Embryologie des Salmones, 8vo, with Atlas folio. Neufchatel, 1842. 



