1174 Stozvard.—A myloclastic Secretory Capacities of the 
cultures ' described, to a depth of io mm., were prepared and transverse 
sections of unboiled endosperms were placed in these ; before the complete 
setting of the medium some of the sections sank to the bottom, others 
remained at the surface ; on the latter were placed, on separate plates, 
embryos and fragments of aleurone layers. 
Starch dissolution as usual occurred in the sections at the surface, and 
also finally (after 3-3 weeks) in those at the bottom of the medium, “but 
little action was noticeable on the cell walls. 
The experiments showed very clearly that amylase of secretion had 
graduallydiffused throughout the medium. The comparatively small amount 
of action on the cell walls, in the light of the experimental results yielded 
by the miniature cultures, must be taken to mean that the cytase, owing to 
the immensely large volume of culture medium, was so greatly diluted that 
its action was rendered almost inappreciable. 
In fine, the results recorded in the present section furnish supple¬ 
mentary evidence of the possession by the embryo and aleurone layer 
of both amylo- and cytoclastic secretory powers. It must be added, in 
view of the fact that disintegration and apparent digestion of the cytoplasm 
take place under the conditions of experiment described, that the possession 
of a proteolytic function is to be ascribed to the embryo and aleurone 
layer. They further support the view that the inner endosperm is incapable 
of inducing the depletion of its starch contents. 
Reference has frequently been made, in dealing with cultures of endo¬ 
sperms, to the corrosion of starch grains, which is a constant feature in these 
experiments, and to the invariable absence of this feature in inner endo¬ 
sperms, under similar experimental conditions, the inference being that 
the amylase secreted by the aleurone layer attacks and erodes starch grains 
in a manner which it is impossible to differentiate from that induced by the 
amylase secreted by the columnar epithelium. In the present section 
direct evidence has been rendered available by the actual placing of aleurone- 
layer fragments on barley starch grains, and subsequently demonstrating 
the characteristic features and progress of the action. It has also been 
shown that when starch-paste conversions are carried out with the aleurone- 
layer secretion the constants obtained do not differ greatly from those 
furnished by similarly conducted conversions with embryo secretions, and in 
either case the conversion proceeds to the stage which no longer gives 
a coloration with iodine. These facts are regarded as evidence that the 
cells of the columnar epithelium and aleurone layer are, physiologically 
speaking, identical. 
The phenomenon termed { double fertilization ’ or ‘ triple fusion ’ has 
been known for a long time, and the possibility of its widespread occurrence 
has received general acceptance from the majority of botanists. This 
phenomenon, although it is claimed that it occurs in Zea (maize), has not, so 
