234 



BOTANICAL MICROTECHNIQUE. 



cold solution of di-sodium phosphate (Na,HPO 4 ); but in a 

 boiling concentrated solution of the last they slowly dis- 

 solve. This author states that these bodies are formed of a 

 knot of thread, and he regards them as probably related to 

 nuclein (cf. 236).] 



15. Tannin-vesicles. 



418. In the cells of many Zygnemacea are found strongly 



refractive globular structures, which, as 

 Pringsheim (II, 354) recognized, contain 

 large quantities of tannin and are com- 

 monly termed tannin-vesicles. Such tan- 

 nin-vesicles have also been observed in 

 various Phanerogams (cf. af Klercker 1, 15). 

 But, while they are 

 usually present in 

 the Algae m e n - 

 tioned in large 

 numbers, and are 

 of small size (cf. a 

 Fig. 58, g\ in the " 

 Phanerogams they 

 are usually single 

 or only a few in a 

 F.G . S 8.-Ce,i oi iMeso- cell and are of *^^JS$^ 



vesicles 5 / pyJSSff relatively large ***' * tannin-vesicle ; ,, nu- 

 es, />, pyrei / & cleus ; c, chloroplasts. 



size, as in the bases 

 of the petioles of Desmanthus plenus (cf. Fig. 59, g\ 



419. These tannin-vesicles always arise, as Klercker (I, 

 22) has shown, in the protoplasm, from which they are 

 most probably separated by a true precipitation membrane 

 of albumen tannate. Whether they contain other sub- 

 stances than tannins cannot at present be certainly stated ; 

 but, at all events, they cannot contain dissolved proteids, as 

 Klercker (I, 36) has shown. 



420. In the investigation of the tannin-vesicles, all the 



