AETIFICIAIi HATCHING OF SPAWN. 63 



When you have conveyed the ova to the resting- 

 place prepared for it, distribute it in a spoon, as 

 hefore directed; and henceforth, until the period of 

 hatching, disturb it as little as possible. Now and 

 then you may desire to look at the ova, to see how it 

 is progressing. If covered, remove a stone or two 

 carefully ; take a smaU glass tube, of about a third of 

 an inch in diameter, and place the mouth of it over 

 the ova you desire to examine; stop the other end 

 with the forefinger, and thus, by suddenly removing 

 it, the egg vrill be drawn up into the tube, with a 

 small portion of water. Place the forefinger again 

 upon the orifice, and turn up the end where the ova 

 is, q^uickly, so that it remain in the tube. You may 

 then drop it into an egg-cup or wine-glass, half full of 

 water, and survey it at your leisure. A powerful 

 glass, or the microscope, will enable you to note the 

 singular and gradual development of the ova. Here- 

 with I give a cut of the tube or apparatus used at 

 Huningue for the purpose of testing ova and even 

 small fish. It will be seen that with this it is not 

 necessary to drop the ova, &c. into the glass or cup, 

 but it may be held in the bowl part of the tube. 

 If, however, a nearer view be needed, by turning the 

 pipe upside down the contents can be discharged. 



For some time, little change will be observable in 



