[LLOYD] TANNIN IN THE LIVING CELL 5 



the "tannin mass," as I call it for convenience, by comparing its 

 behaviour toward various reagents with that of tannic acid in ap- 

 parently identical physical state. A mass of evidence, which is 

 difficult to digest in brief form, has been accumulated, but for brevity's 

 sake it is necessary to avoid too much detail. I point out, however, 

 e.g., that the dry tannin mass, after treatment with vapour of nitrous 

 ether, swells in cold water, dissolving only upon heating; while dry 

 fragments of tannic acid which has been exposed as solution to 

 nitrous ether do not swell but dissolve slowly in the cold. The 

 behaviour of the tannin mass under this treatment, as observed 

 microscopically, is unequivocal evidence that the tannin mass is a com- 

 plex of substances, of which tannin is one, which has its own colloidal 

 properties different from those of tannin alone. The behaviour of 

 this substance toward the alkaloids, which are weak bases, is very 

 similar to that observed by Loew and Bokorny (I.e.) in the tannin 

 cells of the leaf of the rose (Rosa),- which behaviour is attributed by 

 them to the presence of labile albumin. The same conclusions were 

 drawn by them with respect to Spirogyra, but van Wisselingh denies 

 that albumin enters into the complex. In support of the latter's 

 opinion, I point out that I kept the material of acorn in 20% formal- 

 dehyde for several days. On examination, the tannin masses were 

 found to be dissolved out, while the surrounding cell walls, etc., into 

 which the tannin had diffused and by which it had been adsorbed, 

 showed appropriate reactions. Viewed microscopically the tannin 

 mass was found to dissolve in 40% formaldehyde. Further, after 

 treatment with nitrous ether, the tannin mass, which is now coloured 

 brown with an oxidation product of tannin, which fills the vacuole 

 and which has starch grains embedded in it, fails to react to caffeine,* 

 as does the untreated material. In this latter the characteristic 

 gummy or emulsoidal compound (salt) of the alkaloid and tannin is 

 formed, as above pointed out. It follows that the material which 

 occupies the space of the original tannin mass, after oxidation of the 

 tannin, is an emulsoid of probably carbohydrate nature. 



The presence of a second substance is further indicated by the contrast in the 

 behaviours of the tannin mass and flakes of dried tannin, as the following observations 

 show: 



If a saturated solution of ammonium molybdate in ammonium chloride is 

 applied to dry tannin masses, these first absorb water and then become vacuolated. 



^Verbal communication accompanied by photograph. 



'Tannic acid, after being acted upon by nitrous ether, dried and redissolved in 

 hot water (which takes place slowly) gives no reaction with caffeine but gives a blue 

 reaction with iron salts. 



