838 Stoward.—Amyloclastic Secretory Capacities of the 
Calcium sulphate appeared to offer many advantages : it was used suc¬ 
cessfully by Hansteen, by Puriewitsch 3 and latterly by Miss Bruschi, in their 
studies of endospermic depletion, and Ford and Guthrie have shown it to 
be one of those salts which solubilize the c latent ’ amylase of the resting 
grain. 
Experiments with endosperms and inner endosperms were therefore 
carried out on this substrate in the following manner:— 
In each of a series of Petri dishes was placed a layer of calcium sul¬ 
phate 15 mm. in depth; these were sterilized and, after cooling, sufficient 
sterilized tap-water was added to form a semi-solid stratum. The objects 
(endosperms and inner endosperms) were then inserted by their proximal 
ends, for a distance of a few millimetres, into the substratum, and finally 
water added in such quantity that, on tilting the dish slightly, water was 
visible at the lower margin of the semi-solid stratum. Under these con¬ 
ditions the objects received sufficient mechanical support to retain their 
vertical positions throughout the course of the experiment, and were 
virtually partially immersed by their proximal ends in a saturated solution 
of calcium sulphate. The conditions selected probably afford better con¬ 
ditions for the diffusion processes, both inward and outward, than the use 
of the solid gypsum columns adopted by Hansteen and others. 
Typical examples of the results furnished by experiments established 
on these lines are given in the table which follows. They are not illustra¬ 
tive of the results furnished by one series of experiments merely, but of 
many similarly conducted essays. 
After transferring to a beaker, the calcium sulphate substrate was 
treated with almost boiling water to arrest further amylolytic action, the 
mass well stirred and thrown on a filter, washed, cooled, and the filtrate 
and washings diluted to 100 c.c., and duplicate copper reductions carried out 
by Bertrand’s method. 1 
The sterility of the medium was controlled by inoculating small quan¬ 
tities of liquid and solid portions of the substratum into yeast-water- 
dextrose-maltose medium and incubating for 14 days at 30°. 
1 The residues from these filtrates were each evaporated to small bulk, refluxed with 90% alcohol, 
the alcoholic extract filtered and after expulsion of the alcohol examined polarimetrically ; each was 
found to be dextro-rotatory. On treatment with phenylhydrazine each preparation yielded 
apparently a mixture of two osazones. These facts leave no doubt as to the nature of the reducing 
substances found in the various media after termination of the culture experiment. 
