32 M. L. Shorey 
tem, but when it occurs 5 or 6 days later, as it did in some experi- 
ments which I attempted to carry beyond that period, it seems 
to be in some way connected with defects in the amnion, for in all 
these cases which were examined carefully an aperture was found 
in the region of the operation. This would agree with the work 
of other observers who have shown that anamniote embryos 
may develop normally for a time, but that later this defect is fatal. 
That the amnion can, however, regenerate if not too extensively 
injured and form a completely closed sac was demonstrated by 
other experiments in which I knew it to have been injured by the 
operation, so that an improved technique would doubtless obviate 
this difficulty. 
Killing and fixing in sublimate zctic, and staining with Dela- 
field’s haematoxylin and Orange G was found to be entirely satis- 
factory for the end desired, and was the method used inthe majority 
of cases. 
As the effects would naturally be most pronounced after a con- 
siderable interval of time I began with a study of the oldest 
embryos, those killed between 5 and 6 days after the operation. 
When the conditions in these had been ascertained, specimens 
killed respectively 4 days, 3 days, 2 days, and 1 day after the injury 
was made were examined, and the results will be given in this 
order. 
Experiments on Embryos After Three Days of Incubation 
Specimens Preserved Five or Six Days After the Operation 
Experiment 538. This egg was incubated 84 hours and was 
approximately i in the stage shown in Fig. 1 at the time of the oper- 
ation. ‘The right wing was removed and the egg returned to the 
incubator for 5 days 5 ae so that when preserved the age of the 
embryo was 8 days 19 hours. ‘The only evidence of the right wing 
was a small rounded elevation scarcely noticeable on a casual 
examination. The wound was completely healed and the embryo 
vigorous and entirely normal externally except for the missing limb. 
