348 REPORTS ON THE STATE OF SCIENCE. 
In the report presented to Section D at the York Meeting, the 
results of some such measurements were communicated. These results 
showed (1) that there was a tendency for the first furrow and the sagittal 
plane to coincide, though no correlation or causal connection could be 
demonstrated between them ; (2) that there was a much stronger tendency 
for the sagittal plane to lie in the plane of symmetry of the unsegmented 
egg, and a considerable correlation between them ; while (3) the first 
furrow tended either to coincide with or to lie at right angles to the place 
of symmetry. 
This statement is however not final, for the possibility of a dis- 
turbing influence being exerted by certain external factors has still to be 
taken into consideration. The factors in question are: (1) the mutual 
pressures exerted by the jelly-membranes, and (2) the position occupied by 
the freshly laid egg. With regard to the first, it is well known that the 
direction of the first furrow may be determined by pressure ; and as far 
as the second is concerned it is possible that gravity may act upon the 
semi-fluid contents of the egg during the short interval (half a hour) 
which elapses before the definitive position, with the axis vertical, is 
assumed. 
These possibilities have now been experimentally tested, and it has 
been found in the case of the angle between first furrow and sagittal 
plane that 
(a) When the axis is originally vertical, and the eggs spaced, the 
standard deviation is o=30°94'71 (n=426), 
(3) When the eggs are spaced but the axis horizontal c=31:23+-90 
(n=281). 
(y) When the axis is vertical, but the eggs closely packed o=33-65 
+:°56 (n=793). 
(¢) When the axis is horizontal and the eggs packed together 
It is evident that both these factors interfere with the ‘typical’ 
relation between first furrow and sagittal plane, for when both are removed 
the tendency of the two to coincide increases markedly. 
The value obtained for the standard deviation when both factors exist 
is approximately the same as that obtained from last year’s measurements 
when disturbing influences were not allowed for, viz., c=40°394-64. 
At the same time it should be pointed out that in a state of Nature 
the eggs are laid with their axes making all angles with the vertical and 
subjected to the mutual pressures of their jellies in the bunch. Probably, 
therefore, in ‘normal’ development the correlation between first furrow 
and sagittal plane is very slight if not zero. The correlations in each 
of the above four experiments remain to be worked out. 
