41 
; 
to 1,33°/,, on the average a little more than in the two preceding 
eases. However, the numbers fall within the limits of probable error, 
so we may put the last three cases about equal. 
At 7 am. the number of karyokineses has again greatly fallen. 
On 9255 nuclei there are 49 divisions, i.e. from 0,46 to 0,60°/,. 
The cycle is now complete and we are again at 10°/, a.m. without 
a single karyokinesis. 
We see from this that there is a maximum number of karyoki- 
neses during the evening and night at 6'/, p.m., 10'/, p.m. and 
2'/, am. and a total absence of karyokinesis at 10'/, a.m. The 
intermediate hours, 2'/, p.m, and 7 a.m. show a rise and fall. 
Let us now see whether some regularity can be perceived in the 
succession of the various stages. 
At 2°/, p.m. — when the process of division may be considered 
to have just started — we only meet with the two youngest stages 
of division. At 6'/, p.m. we find all stages except the last; the two 
youngest stages are most frequent. At 10', p.m. we have the same 
stages as at 6'/, p.m., the medium stages begin to prevail here. 
Remarkable is here the rise in the last stage but one. 
At 2*/, a.m. we find again several nuclei in the very youngest stage. 
However, we also see nuclei in the very last stage, namely 2 young 
nuclei. (It is not always easy to settle whether we have to do with 
2 young nuclei. Only such cases have been mentioned in which the 
chromatine was still clearly visible as two lumps belonging together, 
as in the preceding stage, with this difference, however, that here 
no division-splindle and centrosomes were visible, as was the case 
in the last stage but one.) For 7 a.m. the same holds as for 2'/, a.m. 
Hence there is no perfect regularity in the process. At the later 
hours of the cycle a larger number of young stages occur than at 
the middle hours. But it is remarkable indeed that at the earlier 
hours, namely at 2'/, p.m. only early stages of division are found 
and that at the later hours, 10'/, p.m., 2?/, a.m. and 7 a.m. the 
two last stages of division have greatly increased in number. 
Cornea. Of the cornea the outer stratified epithelium was 
examined with regard to the number of karyokineses. A much 
smaller number of divisions was found than in the preceding tissue. 
This cannot be wondered at if it is borne in mind that the mesen- 
tery grows more rapidly than the cornea. 
The following table (See p. 42) gives the required information. 
Expressing again the total number of karyokineses in percentages 
and taking into account the probable error, we obtain the following 
figures: (See p. 42) 
