[9] PROPAGATION OF WHITEFISH AT NORTHVILLE, MICH. 561 
their way into the pan at all. This loss can be obviated to a certain 
extent by holding the male in a horizontal position, when the result of 
each titillation will usually be driven directly into the pan. When there 
is an abundance of ripe males the observance of this precaution is not 
material ; but when there is a scarcity—frequently the case—the saving 
of every particle of this fluid is of great importance, as each drop may 
represent the future life of thousands of fishes. 
If the first or any subsequent ejection of milt from any male is streaked 
with blood, cast him aside. 
Not more than one large or two small females should be handled be- 
fore using the males. It is a good plan to alternate one or more males 
with each female, adding milt to the eggs as soon as possible after they 
are taken, having a few of the former selected and placed within easy 
reach before manipulating the latter. No definite rule can be given as 
to the number of males to be used for each female, owing to the great 
variance of yield in both sexes; still it is evident that a sufficient quan- 
tity of the male principle has been mixed with the eggs if, when the pan 
is tilted, a milky coating is seen crawling on the bottom, for, when used 
as freely as this it seems impossible that any eggs could have escaped 
contact with the spermatic fluid, all that is necessary to accomplish im- 
pregnation. <A feather or the tail of a fish—nothing harsher—should 
be used in mixing the milt andeggs. The same end may also be secured 
by swaying the pan, but the first plan is preferable, as a complete dif- 
fusion of the milt can be effected in much less time. 
After thoroughly fertilizing the eggs allow them to stand three to five 
minutes before adding water; then add about a half dipperful and mix 
with a feather or by tilting and swaying the pan. But do notdelay the 
addition of water much beyond the time specified, as a portion of the 
eggs will, if neglected but a short time, adhere to the pan and collect 
in twos, threes, and bunches, subsequently requiring considerable extra 
labor for their separation. Continue to add water as before at intervals 
of five minutes until the pan is nearly full; then pour off, rinse the eggs 
well through two or three waters, and transfer to one of the large pails 
previously filled with fresh water, filling no pail, however, more than 
half full of eggs, giving them an hourly change of water thereafter— 
oftener if practicable, the oftener the better—until removed to the float- 
ing boxes or carrying cases. As soon as water is given the eggs they 
immediately begin to absorb it with gréater or less greed, depending on 
the temperature of the water—the warmer the water the more rapid the 
process—the impregnated eggs, also, absorbing water more readily than 
the unimpregnated. This Sbuoriien of water also causes them toswell 
proportionate to the quantity so imbibed, and harden gradually, grow- 
ing firmer for several hours. They may be deposited in the floating 
boxes any time afier being thoroughly washed, but should not be placed 
on trays for at least four to six hours, by which time they will become 
sufficiently hardened to spread in single layers. A greater depth than 
S. Mis. 29 36 
