254 BOTANICAL GAZETTE [NOVEMBER 
evidently the concentration is near the border line of injury, since 
1-400 does not definitely display such uniform depression of 
respiration. It was desired to compare the respiratory rates of 
young seedlings from treated and untreated wheat, but as yet 
technique has not been devised which avoids the luxuriant devel- 
opment of Rhizopus in the warm moist atmosphere of the 
- respirometer. In these tests, as in those with the seeds alone, 
special care was used to avoid air infection of the respirometers. 
Just previous to a running, the interior of each jar was wiped out 
with cotton moistened with mercuric chloride (1-1000). The 
further precaution was taken of flaming the gauze on which seeds 
and seedlings were placed. KKARCHEVSKI, as quoted by BAILEY and 
GuRJAR (9), found the energy of wheat respiration as measured by 
carbon dioxide releasal twelve times greater for the embryos than 
for the entire seeds. This seems to indicate that the data may be 
more largely influenced by factors affecting the embryos than other- 
wise. The facts that formaldehyde denatures proteins, that the 
embryo is rich in proteins, and that the respiration data show the 
effects of formaldehyde treatment, make it possible that the injuri- 
ous effects of formaldehyde are intimately connected with injury 
to the embryo itself. This is in harmony with the findings of 
CoLins (18), in a study of the coat of the barley grain, that the 
entry of solutions and hence the seat of selectivity is in the germ 
end of the grain. 
It is of interest in this connection to note that although Miss 
Hurp (33) believed the injurious effects of formaldehyde to be 
attained by a slow absorption of the gas liberated from paraformal- 
dehyde, and although these studies of the penetration of formal- 
dehyde do not show any sudden penetration of the fungicide, 
nevertheless within a period of time as short as three to six hours 
during respiratory determinations, some effect is exerted upon the 
seed which very definitely modifies the respiratory rate as compared 
with water soaked controls. One can but wonder whether here, 
as in the case of the studies of CRocKER and KnicuT (24), we may 
not have in plant responses a more delicate indicator of injury 
than are the chemical reactions commonly used in detecting these 
injurious substances. 
