94 SUMMARY OF CURRENT RESEARCHES RELATING TO 



einpyreumatic substances had penetrated into the flesh, and had 

 accumuLated chiefly near the centre round the pips, and were found 

 even in the rachis of the bunch. The skin of the grapes was also 

 covered with an external deposit of various hydi'ocarbons. The con- 

 clusion to be deduced is that gaseous substances are able to penetrate 

 even a thick epidermis, and to be absorbed by the subjacent tissue 

 without previous solution in water. 



Protein-Crystalloids of the Potato.* — According to H. Karsten 

 the crystalloids of the potato are cells in which other cells, the 

 "nuclear cells," are inclosed. Their growth is readily followed in 

 boiled potatoes after digesting in slightly acid solutions of alkaline 

 phosphates, from which treatment they in no degree lose their power 

 of development ; their cellular nature being very distinctly shown. In 

 many respects they bear a strong resemblance to bacteria. 



Hypochlorin."!" — Experimenting on the hypochlorin-crystals of 

 Pringsheim,:}: A. Meyer agrees with the conclusion of Frank § that 

 this substance is identical with Hoppe-Seyler's chlorophyllan. He 

 finds a convenient reagent for its solution to be glacial acetic acid. 

 If leaves of Iris germanica are laid for three days in hydrochloric 

 acid (1 part HCl and 4 parts water) until a few brown crystals 

 appear, and then heated with glacial acetic acid, the green drops 

 which had formed dissolve, and fresh brown crystals appear in 

 addition to the old ones ; or they can be obtained at once from the 

 leaves by treatment with the acetic acid. The reaction of these 

 crystals with various reagents is the same as that of those formed 

 by the agency of hydrochloric acid, and is identical with that of 

 chlorophyllan ; a solution in castor-oil shows also precisely the same 

 spectrum as that of this substance. 



Crystals of Chlorophyll.il — J. Borodin describes crystals obtained 

 by the slow maceration of sections of green leaves in alcohol, and 

 then slow drying under a cover-glass, which are not identical with 

 the chlorophyllan of Hoppe-Seyler. They were obtained from a 

 great variety of ditferent plants, but only from about one-fourth of 

 those examined, most constantly from the Pomacete and Amygdalefe. 

 They are probably a compound of chlorophyll with some unknown 

 substance. They are much more abundant in leaves of middle age 

 than in either the oldest or youngest. Their colour varies from 

 pale green to nearly black, and their size and shape are very variable ; 

 they have no effect on polarized light. Their properties are constant 

 and uniform ; they ditfer from chlorophyllan in being very stable 

 under the influence of sunlight, as also under that of dilute acids ; 

 they neither dissolve nor swell in hot or cold water, but dissolve 



* Phaim. Centralh. f. Deutscbland, iii. (1882) pp. 185-8. See Bot. Centralbl., 

 xi. (1882) p. 341. 



t Bot. Ztg., xl. (1882) pp. 530-4. 



X See this Journal, iii. (1880) pp. 117, 480 ; i. (1881) p. 479. 



§ Ibid., ii. (1882) p. 528. 



II SB. Naturf. Ges. St. Petersburg (Bot. Sect.). See Bot. Ztg., xl. (1882) 

 pp. G08, 622. 



