206 GENERATION. 



a flock of geese for more than fifteen years, and by depriving them of 

 their first brood in my investigations, they commonly bred again the 

 same season. 



As hours make a difference in the first days, it becomes necessary to 

 examine in the night as well as in the day ; by which reason, the latter 

 brood in the summer is best adapted, having then short nights. 



Of the different Methods to be taken to examine the Progress of the 

 Chick in incubated Eggs. 



The first thing necessary is the breaking and removing part of the 

 shell of the egg, which is to be begun at the upper part. In the 

 breaking of the shell of the egg, when the chick is young, as at twelve, 

 twenty-four, or thirty-six hours, it should not be broken where the chick 

 is, that is, not at the very upper part, but a little way from it, and 

 break it round this most prominent part for the breadth of a shilling : 

 this is with a view to avoid the sharp corner of the shell wounding the 

 membrane and hurting the first rudiments of the chick. Then take off 

 the shell, leaving the lining of the egg on ; then remove gradually the 

 membrane from over the chick. This must be done with great care and 

 attention ; it should be taken off in layers with a pair of forceps. The 

 egg so prepared should be put into warm water as high as the chick, 

 but not allowed to cover it, as water soon kills it. In this way it may 

 be kept alive some hours. It may be necessary to remark, that, while 

 the heart of the chick acts, the blood keeps red; but as soon as it 

 ceases to act, the blood becomes almost immediately pale, and soon loses 

 its red colour ; therefore it is necessary to keep the animal alive as long 

 as possible*. When it is examined sufficiently in this state, then, to 

 see the body of the animal still better, the membrane should be cut all 

 round beyond the foetal circle, and the whole taken off under water ; 

 and then have a piece of thin black ivory to slip under it, and put the 

 whole into spirits, which will coagulate the completest formed parts, 

 and bring them to view upon the black ground. In this way I have 

 been able to bring parts distinctly to view that before appeared to be 

 involved in a cloud ; also we can bring them under a much larger 

 magnifier, and bring out parts that neither their situation nor glasses 

 could expose. 



* Various were my attempts to effect this, but mostly in vain. I conceived that 

 when I had just exposed the little animal by putting it into water, heated to about 

 204 degrees, just covering the egg, I might keep it alive by these means, and observe 

 in the same chicle the whole progress of growth ; but it soon died ; therefore I was 

 obliged to have recourse to a succession. 



