402 The Physiology of Plants BOOK in 



knowledge of the number oi germinating seeds which yield 

 it, but added little to our acquaintance with the actual 

 process it carries out. Following him we had a large number 

 of workers who studied its distribution in the plant. In 

 1877 Kosmann found it in leaves and shoots, in 1878 

 Baranetzky found it in the tubers of the potato, as Payen 

 and Persoz had done before him, and in the buds and other 

 green parts of so many plants that he suggested it to be 

 universally present in vegetable tissues. Krauch in 1879 

 and Brasse in 1884 detected it in leaves and shoots, 

 and the latter writer added materially to the accuracy 

 of our knowledge of its powers. In 1889 Kjeldahl, and 

 in 1890 Brown and Morris, determined its presence in 

 the barley grain before germination set in. In 1893 the 

 writer found it in pollen-grains and showed that it plays 

 a leading part in the nutrition of the pollen-tube. In 

 1883 it was shown byDuclaux to exist mAspergillus, a dis- 

 tribution which seems strange when we remember that the 

 Fungi contain no starch. Errera's discovery of glycogen 

 in these organisms, made about the same time or a little 

 earlier, removes, however, any difficulty on that account. 

 Bourquelot and Herissey confirmed Duclaux's observation in 

 1895, and showed that it is not uncommon in this group. 

 Some very important and far-reaching observations were 

 made by Haberlandt and by Brown and Morris in 1890 

 as to its distribution and its mode of formation in the 

 germinating grains of barley and rye. These observers, 

 working independently, ascertained that during the germina- 

 tive processes, in addition to a certain small amount in 

 the cells of the endosperm, a considerable quantity is 

 secreted by the cells of the Kleberschicht, or aleurone 

 layer; immediately below the outer coating, and still more 

 by the epithelial cells of the scutellum or absorbing organ, 

 and that the enzyme diffuses thence into the starch-con- 

 taining tissue. The importance of this discovery lies largely 



