54 2 
Richards . — -The Respiration of 
the air. He cites the results of some experiments with 
potatoes which had been hollowed out in the centre, the 
cavities being filled with water, and again sealed from the air, 
under which conditions their respiration still continued very 
strong. But on the other hand must be considered Stich’s 1 
results already referred to, which point to another explanation. 
Experiments similar to those of Stich’s with gelatin were 
tried, but of longer duration, so that it was necessary to use 
clay for the covering of the wounded surfaces. In Experi- 
ment 7, with potatoes the quarters of which had been covered 
with clay at once after cutting, the four determinations taken 
on the day of the injury did not show the expected increase. 
On the next day, when the ordinary maximum for a similar 
quantity of potatoes should have been about 1 5 mg., it was 
only 7*60 mg. ; while after the lapse of seven days the 
amount was practically nothing. After the removal of the 
clay there was a sudden and marked increase of the C 02- 
production. The cut surfaces of the potatoes which had been 
protected by the clay were not absolutely fresh, being covered 
with a thin layer of corky material, which, by the way it 
may be mentioned, was not disturbed in the removal of the 
covering. This is shown even more clearly in the case of 
Experiment 13, where the clay was not applied until the time 
of the maximum respiration. Immediately there followed 
a decrease, which again gave place to an increase when 
about twenty-four hours afterwards the clay was removed. 
The carrots (Expts. 16 and 17) treated in a similar manner 
exhibited much the same effect ; in both the cases cited the 
application of the clay hindered the usual increase of C 0 2 , 
and, when after some time the clay was taken off, the respira- 
tion at once rose to a very considerably higher point, where 
it remained, with only a slight decrease, for several hours. 
A similar result was also obtained in another series with 
potatoes, in which case the tubers were simply deeply incised, 
not actually cut through, and were then at once very tightly 
bound with soft string. At first a slight rise in the respiration 
1 1 . c., Versuche, 13-15. 
