in the Fixed Principles of the Egg during Incubation. 69 
The analysis of the yolk of the recent egg shews it to con- 
sist of the following principles in the proportion mentioned 
Grs. 
Water, 
170.2 
Albumen, 
55.3 
Yellow Oil, - 
- 91.0 
316.5 
Experiments on the Egg at the end of the first week of 
Incubation. 
On the supposition that the egg originally weighed 1000 grs., 
it has generally lost about 50, at the end of the first week ; and 
the weights of the constituent principles of two eggs in their 
moist state, were as follows : 
No. I. 
No. II. 
Grains. 
Grains. 
Unchanged albumen, - 
232.8 
247.1 
Modified albumen, .... 
179.8 ) 
Liq. amnii, membranes, blood-vessels, &c. 
97.0 V 
275.2 
Animal, - - 
22.0 ) 
Yolk, - - ----- 
301.3 
324.5 
Shell and loss, 
167.1 
153.2 
1000.0 
1000.0 
As the present inquiry seems to be in some respects illustra- 
tive of the subject, I shall offer a few remarks on the general 
phenomena presented by the different constituent principles of 
the egg at those periods at which it has been submitted to exa- 
mination. 
It has been observed, that soon after incubation has com- 
menced, the yolk becomes more fluid than usual, and that as 
the liquor amnii increases, that portion of the albumen occupy- 
ing the upper and larger end of the egg begins to assume a pe- 
culiar appearance. In the present experiment, in which the 
egg was previously boiled, the liquor amnii and portion of al- 
bumen in question, about the eighth day, exhibited something 
of the appearance of curds and whey. Nor was the analogy 
confined to appearance only, for the curdy looking matter, 
which was of a yellow colour, and which I have termed modified 
albumen , resembled the coagulable part of milk in its proper- 
ties, in so far as to contain intermixed with it an oily or butyra- 
