GERMINATION OF SEEDS. 221 



homogeneous optically, or contain inclusions. The latter 

 are principally proteinic crystals, the crystalloids, or such as 

 are usually spheroidal, the globoids ; crystals of calcium 

 oxalate also occur occasionally. The globoids may pos- 

 sibly consist of the compound or mixture described by 

 Winterstein, 1 which is the calcium-magnesium salt of an 

 acid phosphoric ester, that yields inosite on decomposi- 

 tion. The aleurone-grains are embedded in a proteinic 

 matrix ; both may suffer dissolution during germination, in 

 which case the matrix is composed of necroplasm, 2 this 

 being the case in certain endosperms ; or only the grains 

 may be thus affected, when the matrix consists of hypno- 

 plasm, 3 as is the case in the cotyledons of seeds. Previously 

 to dissolution the substance becomes swollen and hyaline. 



Inasmuch as appreciation of the various theories, founded 

 on the occurrence of certain nitrogenous compounds during 

 germination, requires knowledge of the products of artificial 

 proteohydrolysis, it is perhaps advisable to devote a few 

 words to the subject. 



The question of artificial proteohydrolysis has been 

 attacked by several observers. 4 As a result of their in- 

 vestigations, it is known that the products fall principally 

 into three groups — (1) nitrogenous bases, (2) aliphatic 

 amido-acids, and (3) aromatic amido-acids. Ammonia is 

 also formed. Examples of the first group are — lysin (dia- 

 mido-caproic acid), lysatinin (a compound creatin), arginin 

 (guanido-a-amido-valerianic acid), histidin. Examples of 

 the second group are — aspartic acid (amido-succinic acid), 

 glutaminic acid (a-amido-glutaric acid), a-amido-valerianic 

 acid, and leucine (a-amido-caproic acid). The third group 

 is exemplified by — phenyl-a-amido-propionic acid and tyro- 

 sine (para-hydroxyphenyl-a-amido-propionic acid). Several 

 other products have been obtained, but they have at present 

 no demonstrated connection with the subject under dis- 



1 Ber. d. deut. ch. Ges., xxx. (1897), p. 2299. 



2 See Science Progress, loc. cit. 3 Ibid. 



4 Notably by Hlasiwetz and Habermann, Horbaczewski, Schiitzen- 

 berger, E. Baumann, E. Salkowski, Nencki, E. Brechsel, A. Kossel, E. 

 Schulze, S. G. Hedin, and others. 



