46 



THE VEGETABLE CELL IN GENERAL. 



protein crj-stal-like bodies, and the protein basis or stroma in 

 ■which all of these are held. 



The protein basis sometimes, if not alwaj's, appears to consist 

 of two substances, differing in their solubility in water, and com- 

 mingled as granulose and 

 cellulose are in starch- 

 granules. While the pro- 

 tein basis is generallj' verj' 

 soluble in water (not per 

 se, but owing to the pres- 

 ence of potassic phos- 

 phate), the protein crj'stals are insoluble, or onlj- slightly affected 

 by it, usually becoming more or less swollen. After solution of 

 the protein basis has taken place, a delicate membrane is left 

 behind, and through this transparent film tlie protein crystals 

 are clearly seen. The relatiA'e amounts of protein basis and 

 protein crystals varj- wideh' ; in some cases the former appears 

 to be wanting, Ihe latter whollj" filling the interior of the mem- 

 brane. Such crystals appear in potato-tubers in the form of 



small cubes. Protein crystals of great beauty are easily dem- 

 onstrated in the endosperm of the common Brazil-nut (Ber- 

 tholletia). Very instructive phenomena are presented when 

 different sections of the seed are subjected to the following 

 reagents; (1) osmic acid (one per cent solution) ; (2) heematoxylin 



Pig. 14. Single iirotein grnnnles treated as in Pig. 12. '{o. (Pfeffer.) 



Fig. 15. Protein granules tVnm Silybum marifinum. In the cell on the left they have 

 crystalline contents; in that on the right, globoids This section was taken from the 

 cotyledons of a dormant seed, and after treatment with mercuric chloride in alcohol was 

 placed in water, ^nfl, (PfefTer.) 



Fig. 16. The mesh of the ground mass of the cell has been cleared by dilute potassic 

 hydrate and hydrochloric acid, n = nucleus. ^\'^. (Pfeffer.) 



Fig 17. Cells from the cotyledons of a germinating seed which has just ruptured the 

 seed-coat. The protein granules have disappeared, but their contents are recognizable, 

 'p. (Pfeffer.) 



Fig. 18. Silybum marianum. Cell from the cotyledon of a nearly ripe seed in which 

 the formation of protein granules has just begun. ^5". (Pfeffer.) 



