450 Drs. S. M. Copeman and H. W. Hake. [June 19, 
Table C gives a summary of the results which we obtained and we have 
also included previous results for the sake of general comparison. 
We found in the half hour’s digestion, for mice over twelve months, the 
average in Series 12 was 0:1129 (10 stomachs), with a variation from the low 
figure 0:0611 to 0°2037 per cent. and in Series 16 the figures vary from 
01243 to 0°1765 per cent., with an average of 0°1451 (7 stomachs). On 
the other hand, for mice under three months we obtained an average of 
0-1881 per cent., with a variation from 0°1438 to 0:2167 per cent. (13 stomachs). 
The general average for all half hour experiments is 0°1530. 
It seems to us, with this very considerable variation, scarcely worth while 
to continue the investigation of the half hour period. 
Taking the one-hour period of digestion, the average results are more 
uniform, although there are considerable variations. The average for mice 
over twelve months (144 stomachs) being 0°1488, while that for mice under 
three months (55 stomachs) is 0°14495. 
As regards the one-and-a-half-hour period, the average results were also 
very uniform and the variation distinctly less, the average for mice over 
twelve months being 0:1826 per cent., while that for mice under three months 
is 0'1866 per cent, the extreme variations being 0:1515 and 0°2643 per cent. 
From these figures it is evident that no definite period of digestion is 
indicated from these experiments; all that can be said is that some mice 
have attained a maximum at half an hour, and most have attained a maximum 
at an hour and a-half, while at one hour a large proportion have attained 
amaximum. The explanation of this variation undoubtedly lies in the fact 
that mice are in the habit of continually feeding, and that therefore the 
intervals of rest from feeding are comparatively rare. 
We next made further experiments as to the secretion of yada ys acid 
by mice with transplanted tumours during periods of digestion of one hour 
and one and a-half hours respectively. A summary of the results obtained 
is given in Table D, in which are also included our previous experiments, for 
the purpose of general comparison. 
It will be seen from an inspection of Table D that the results for 
one hour's digestion of mice with non-ulcerated tumours (Series 6 to 10) 
gave an average of 0°1627 per cent. (183 stomachs), with a variation from 
01393 to 0:1964 per cent.; while mice with ulcerated tumours (Series 6 to 8) 
gave an average of 0°2100 per cent., with a variation of 0:1856 to 02439 per 
cent.; the total average for these 235 stomachs was 0:1732 per cent., all the 
mice being over twelve months. 
For mice under three months with transplanted tumours (Series 29 and 
27), four gave an average of 01856 per cent. and seven an average of 
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