MANUAL OF FISH-CULTURE. 147 



fisli whicli have been dead some minutes the milt is lumpy and flows 

 only in drops. A teaspoonful will fertilize 40,000 to 75,000. After the 

 milt has been applied, from half a pint to a pint of water from the river 

 is added and the pan given a slow rotary motion, continued till the milt 

 is thoroughly mixed, when a milky appearance is imparted to the water. 

 When the river water is turbid, clear water must be obtained before work 

 is commenced. 



In gill-net boats eggs thus treated will expand without further imme- 

 diate attention, for there is sufficient motion from the boat to prevent 

 clotting; shad eggs do not "cement" when the milt is applied to them, 

 as in the case with salmon and trout eggs ; but they adhere, and if left 

 perfectly quiet, as on shore, a large proportion will be lifeless. Those 

 comprising the lower strata may either lack sufficient expansive power 

 to absorb water under weight of the others, or in the suction of each 

 separate egg, in the natural tendency to absorb water, they may have 

 a cupping effect upon one another, thus preventing water contact. 

 Whatever the cause, they stick together in one mass, and only those 

 of the upper layers receive sufficient water; the others remain under- 

 sized and die. Large quantities of eggs must be separated, either by 

 agitating the water already in the pan or by the addition of more. 



In one minute after thorough mixing the milt can be washed off with 

 safety, but usually several pans are to be looked after, when the milt 

 may be allowed to remain 5, 10, or even 15 minutes. After the last 

 pan of eggs has been fertilized, they are rinsed, beginning with those 

 first taken, by pouring in a quart of water, placing the edge of the 

 dipper so that the stream is directed between the eggs and the sides 

 of the pan, as the eggs may be injured if the water is poured directly 

 upon them. Then the jian is oscillated, the water being drained over 

 the edge slowly, and, the operation being repeated, the third quart of 

 water is left upon the eggs. The eggs must be well stirred with the 

 inflowing water. 



There need be no fear of applying too much milt. The amount 

 obtained from one fish may be ample for the eggs from two, but it is 

 always better to employ two males. Eggs may look promising for two 

 or three hours, yef never expand to full size or produce fish. They lie 

 at the bottom, and underneath any good ones which may be in the 

 pan; they stick to the fingers, while the good ones will not, nor can 

 they be successfully removed from hatching-jars until after several 

 days' decomposition. By using two pans, good eggs may be separated 

 from bad by pouring, but the process is slow and there is usually no 

 time in the hatcheries for such operations. 



Good eggs are very transparent and so soft and light that they are 

 not apparent to the touch when the fingers are moved among them. 

 When tlie temperature is about 70°, no change is observed for about 

 12 or 13 minutes after the milt is added, but about this time a careful 

 movement of the fingers in the pan discloses their presence, and in a. 



