S toward. — On Endospermic Respiration in Certam Seeds. 445 
A number of preliminary experiments were undertaken with seeds 
steeped in these solutions for varying periods of time, in order to ascertain 
whether their germinative capacity was impaired by this treatment ; the 
seeds after removal from the solution, thorough washing, and further 
steeping in sterilized water, as above stated, being divided into two series, 
one of which was germinated in sand and the other inoculated into tubes 
of 1 % dextrose wort Control series of seeds steeped in sterilized water 
and subjected to similar germinative tests were also undertaken. The 
temperature of germination and incubation was maintained at 20-2i°C. 
The results yielded by the series which had been steeped in the 
copper sulphate solution for six to nine hours, and then placed under 
germination conditions, indicated that this treatment had a detrimental 
effect on radicle development, causing either the feeble development or 
almost complete suppression of this organ ; whereas the growth of the 
plumule was as vigorous and extensive as in the control series. 
Prolongation of the steeping period in the copper sulphate solution 
to twenty-four or forty-eight hours produced much more marked effects, 
fully 50 % of the seeds failing to germinate, and the remainder only 
feebly so. Under these conditions visible penetration of the copper 
sulphate, demonstrated by its blue colour, particularly at punctured or 
damaged parts of the integuments of the seed, and also in the neighbourhood 
of the radicle, was observable. 
In similarly conducted experiments with o-l % mercuric chloride, 
the steeping in this solution being confined to half to three-quarters of an 
hour, and subsequently extended to a total period of twenty-four hours in 
water, the seeds germinated as readily and vigorously as in the control. 
When, however, 0-5 % mercuric chloride was substituted, under otherwise 
precisely similar conditions, only 80 % germinated normally, and of these 
20 % very feebly ; the balance failed to do so. 
The results furnished by the inoculations showed that the series which 
were steeped in the copper sulphate solution for periods of only six hours 
remained sterile for four to five days ; only scanty isolated mould-growths, 
attached to some parts of the surface of certain of the seeds, usually in the 
neighbourhood of the radicle, then made their appearance. Those steeped 
in mercuric chloride remained absolutely sterile until the conclusion of the 
experiment, i.e. after the lapse of fourteen to sixteen days. 
In the series of supplementary experiments with Zea which were 
subsequently undertaken, the material at the termination of each experiment 
was directly placed in tubes of 1 % dextrose wort ; with embryos, intact 
seeds, and endosperms, similar results to the foregoing were obtained. 
With pure endosperms, however, greater difficulty was experienced, yet, as 
the result of many attempts, even with these the attainment of a sterile con- 
dition during the course of the respiration experiment was amply assured. 
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