124 SCIENCE PROGRESS. 



is found to yield the same peptone-like body found in 

 Parameria. 



Besides the laticiferous tissue we find other parts of 

 plants, especially the succulent cortex of stems, the paren- 

 chyma of fleshy roots, etc., the seat of proteid stores. 

 These are not necessarily reserve materials, being possibly 

 plastic material on its way to be used up in con- 

 structive processes. In the large fleshy roots of biennial 

 plants and possibly also in succulent perennial roots the 

 contents of the cells must however be regarded as true 

 reserves. 



In the cortex of the stem of the Manihot there is 

 to be found a globulin a good deal like those already 

 described. It is insoluble in water but soluble in solutions 

 of neutral salts. From the latter it can be precipitated 

 by dialysis, by large dilution or by saturation with solid 

 MgS0 4 . Its coagulation temperature in neutral solutions 

 is 74 to 76°C. 



In the succulent tissue of the lettuce {Lactuca sativd) 

 there is an albumose which is soluble in distilled water and 

 is not coagulated on boiling, but is precipitated by nitric 

 acid or by acetic acid in the presence of potassic ferro- 

 cyanide. 



But little work has been done upon fleshy roots, but an 

 investigation made recently on the asparagus (17) shows 

 in the underground parts of this plant an albumin which 

 gives the characteristic reactions of that group. 



The proteids found in latex and in the various succu- 

 lent tissues described are not in the forms of the aleurone 

 grains of seeds. They are either in solution in the com- 

 plex sap of the cells of the tissue, or are packed away in 

 amorphous form in the meshes of the protoplasm. If 

 cells of these parts are treated with alcohol under the micro- 

 scope the clear, transparent vacuoles become turbid and 

 opaque, indicating a precipitation of the proteid by the 

 spirit. 



The list of proteids so far discovered may be supple- 

 mented by true peptone, which can be determined in ger- 

 minating seeds both of leguminous plants (18) and of cereals. 



