ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 107 



time. Exposed to an electrical induction-current, the leaves became some- 

 what flaccid after fifteen minutes, a brown colour began to show itself in 

 three hours, and in twenty-four hours the destruction was complete. 

 Injection of the intercellular spaces with water hastens the destruction of 

 the tissues. A temperature of 40° C. for a short time appears to have no 

 injurious effect ; one of 55° causes death in about two minutes, one of 75° 

 almost instantaneously. The action of various low temperatures is also 

 described in detail. 



In all these various cases the author determined that the cause of the 

 death of the tissue was the destruction of the molecular structure of the 

 parietal layer of protoplasm, by which it becomes permeable for the acid 

 cell-contents. These pass out of the cells, partly into the intercellular 

 spaces, and the cells thus lose their turgidity. 



Structure of the Cell-wall.* — Herr G. Klebs criticizes Wiesner's recent 

 theory f of the structure of the vegetable cell-wall. He notes especially 

 (1) the absence of any proof that the dermatosomata are organized unit 

 elements and not simply debris particles, and (2) the exceedingly unsatis- 

 factory evidence as to the presence of protoplasm in the cell-wall. He 

 denies the possibility of demonstrating Wiesner's distinction between 

 (a) young living cell-walls in which the majority of the dermatosomata 

 consist of living albumen, with numerous plasma strands between, and 

 (h) an older dead stage in which the dermatosomata consist of cellulose, and 

 have between them a connective mass also of cellulose. Further, he does 

 not consider Easpail's reaction for albumen as altogether trustworthy. 



Multinucleated Cells. ^ — In a number of plants examined (^Polygonum 

 Sieboldii, Acanthus mollis, Podophyllum peltatum, Eschscholtzia californica, 

 Impatiens noli-me-tangere, Dictamnus Fraxinella, Linum pyrenaicum, Poly- 

 gonatum midtifloruvi) Mr. A. E. Grant found, on making longitudinal 

 sections of the stem and petioles, that the cells of the wood-fibres contained 

 several nuclei, sometimes amounting to as many as ten. These nuclei 

 appeared in general to spring from the division of a single nucleus. 



(2) Other Cell-contents. 



Chemical Composition of Chlorophyll. § — Herr J. WoUheim gives a 

 preliminary report of his recent researches on the chemical composition of 

 chlorophyll. 



Hansen's pure chlorophyll is shown to be impure alkaline chlorophyll. 

 That prepared by Tschirch's method is also unsatisfactory. Herr WoUheim 

 has endeavoured rather to form a pure derivative ; but by means of alcoholic 

 ammonia he was also able to obtain a solution of chlorophyll giving a pure 

 spectrum. He points out the objections to the view that Hoppe-Seyler's 

 chlorophyllan and Tschirch's barium-compound are pure substances. He 

 has shown inter alia that iron is not an essential component of bodies in the 

 chlorophyll group. His own treatment resulted in obtaining pure phyllo- 

 cyanin acid, without iron, and free from all ash. He proposes the empirical 

 formula C28H4YN30g. The spectrum of pure phyllocyanin acid appears to 

 be identical with that of chlorophyllan, and a hydrochloric solution of pure 

 phyllocyanin exhibits a spectrum identical with the alcoholic solution 

 (1) of the author's zinc phyllocyanin (B-chlorophyll of Tschirch) and (2) of 



* Biol. Centralbl., vi. (1886) pp. 449-55. f See this Journal, 1886, p. 818. 



J Trans. Bot. Soc. Edinburgh, xvi. (1885) p. 38. 



§ Biol. Centralbl., vi. (1886) pp. 541-2 (Ber. 59 Versamml. Deutsch. Naturf. u. 

 Aerzte, Berlin, 1886). 



