PHYSIOLOGY OF THE OVIDUCT 7, 
it leaves the ‘albumen portion’ of the duct and it takes this at 
nearly the same rate as it did the earlier part. 
It is of interest to note the similarity of this curve showing the 
rate of increase of albumen in the formation of the individual 
egg to the curve previously published by one of the writers!° 
for the increase in weight of egg (which is quite closely corre- 
lated with amount of albumen) with increasing amount of yolk, as 
measured by number of yolks. 
4. It will be noted that the differences in the column headed 
‘weight of yolk’ are in the majority of cases negative. In other 
words, in these instances the yolk of the laid egg is heavier than 
the yolk of the oviduct egg. Now, of course, yolk as such is not 
added during the passage of the egg down the oviduct. This 
being so one would expect that in the long run the yolk of any 
given laid egg would be as often in defect as in excess of the weight 
of the yolk of any given oviduct egg. There is some indication 
that this is not strictly true, but that the ‘laid’ yolk tends to be 
heavier. Such a phenomenon would be in accord with the fact 
definitely demonstrated by Greenlee," in his study of cold stor- 
age eggs, that in the normal, unboiled egg there is a continuous 
transfer of water-from albumen to yolk by osmosis. Certain of 
Miss Curtis’ earlier results had suggested that this was possibly 
the case. 
THE ABSOLUTE AND RELATIVE AMOUNT OF NITROGEN IN THE 
ALBUMEN OF EGGS IN DIFFERENT STAGES OF FORMATION 
While the two lines of evidence presented in the preceding sec- 
tions of the paper amply demonstrate that the thin albumen 
is added to the egg after it leaves the albumen portion of the duct, 
it seemed advisable, because of the novelty of the results to col- 
lect still further evidence of another kind. This evidence, which 
will be set forth in the present section of the paper, has to do with 
10 Pearl, R., Zoologischer Anzeiger, Bd. 35, pp. 417-423, 1910. 
1 Greenlee, A. D., U.S. Department Agriculture Bureau of Chemistry, Circu- 
lar 83, pp. 1-7, 1911. 
12 Curtis, Me R:, loc: cit. 
THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 12, No. 1 
