262 Ethel McLennan: 



properties was displayed hj different parts of the same liyphae, the^ 

 coloured portions being interrupted bv colourless, in a very ii regu- 

 lar manner. In order to ascertain "whether these unstained seg- 

 ments contained protoplasm or were devoid of contents, and thus 

 remained unaltered by the stain, sections were submitted to a 

 second stain foUoAving upon gentian violet. Congo red was chosen, 

 as it stains the cell walls, and,' also the protoplasm The result was 

 that the former uncoloured sections were stained with the red, and 

 displayed dense contents just as is the case with the coloured seg- 

 ments The difference in the staining capacity is probably due to 

 the presence of ferments in certain parts of the hyphal network 

 wherever the ferment is present in any quantity, then will the- 

 **blue" stain be evident. Colour is lent to this idea by the fact 

 that the aleurone layer shows the same staining reactions as the- 

 hyphal layer, llie majority of the cells do not react to the violet 

 stain, but certain of them stand out markedly from the rest, for 

 they stain densely and form very striking portions of the section. 

 The number of such coloured cells varies in each individual grain. 

 In addition, the scutellum repeats the above phenomenon. In this 

 case, the "blue" cells are generally restricted to the epithelial 

 layer of this tissue. 



Brown and Morris (11) have shown that in Eordeum vulgare 

 the secretion of diastase is located in the absorptive epithelium, and 

 in a later paper Brown and Escombe (12) that in addition, the 

 aleurone layer is capable of bringing about marked changes in the 

 endosperm when this is separated from its embryo, and placed 

 under favourable conditions. 



The distribution of the active ferment-secreting cells therefore,, 

 agrees with the staining reactions described above, and supports 

 the view that the coloured segments of the hyphae contain either an 

 enzyme or its fore-runner, and this conjecture is further strength- 

 ened by the later embryo logical work. 



When examining a sample of English rye grass from Ireland, a 

 specimen was occasionally found showing hyphae (which for the 

 most part stained with gentian violet) invading the starchy endo- 

 sperm. Freeman records a similar distribution for grains of 

 Loliiim temiilenfum from Ghent. A careful examination of the 

 aleurone layer of such a grain showed that the hyphae were also 

 running riot here. Instead of the usual inter-cellular course, many 

 hyphae could be made out actually passing into the cells, and in 

 many cases a single hypha could be traced entering and leaving 



