11? RAYMOND PEARL AND MAYNIE R. CURTIS 
Thus in fig. 3 are shown (1) a membane covered egg taken from 
the isthmus of the oviduct of hen No. 8018 shortly before it 
would have entered the uterus, and (2) two normal laid eggs of 
the same bird. The larger size of the latter is obvious. The 
isthmus egg is the one at the extreme left in the picture. 
2. It is apparent from examination of the differences in the 
columns giving albumen weights and albumen-yolk ratios that 
in general the farther down the oviduct the egg proceeds the more 
albumen it gets. Very nearly one-half the total weight of albu- 
men of the completed egg is added in the uterus, an organ hither- 
to supposed to be entirely devoted to shell formation. Clearly 
very much more albumen is added to the egg in the uterus than 
in the isthmus. This, of course, does not necessarily mean any 
more rapid rate of secretion in the uterus, because of the time 
element involved. The egg stays much longer in the uterus than 
in the isthmus. 
3. This brings us to a consideration of the question of the rate 
of secretion of albumen in different positions of the oviduct. We 
have attempted to approach this problem by the graphical 
method. The results obtained are not to be regarded as highly 
accurate in respect to minute details. It is an exceedingly diffi- 
cult matter to get very precise data in the individual instances 
regarding time relations in the physiology of the oviduct. We 
must therefore depend upon average results. The attempt has 
been made in fig. 4 to show graphically the net average results 
from the data collected in this laboratory regarding the time taken 
in the passage of the egg through the several portions of the 
oviduct and the rate of secretion of albumen in the same portions. 
As a measure of the albumen is taken the percentage of the total 
albumen of the laid egg which has been acquired at each specified 
level of the duct. The time is plotted as abscissa, and the per- 
centage of albumen as ordinate. 
It is not possible to recount here in detail all the evidence on 
which the points in this diagram are based. It would involve 
the presentation of considerable material which has. no direct 
bearing on the subject of the present paper. We shall, therefore, 
be obliged to state only briefly, and in some degree categorically, 
