ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 85 



Distribution of Aquatic Plants.* — Dr. G. Hochreutiner Las deter- 

 mined experimentally that seeds of a number of aquatic plants may 

 pass uninjured through the alimentary canal of herbivorous fish, which 

 therefore may aid in the dissemination of aquatic plants. 



(4) Chemical Changes (including: Respiration 

 and Fermentation). 



Production of Proteids insoluble in the Gastric Juice.f — Pursu- 

 ing his investigations on the connection between the production of 

 living albumen and respiration in plants, Herr W. Palladin uses the 

 amount of nitrogen in the undigestible residue as a rough test for the 

 amount of living albumen, though subject to some limitations. He 

 states that nutrition at the expense of sugar takes place much more 

 energetically in the light than in the dark ; and that this is also the 

 case with the regeneration of the proteids. The more refrangible half 

 of the spectrum favours the regeneration of albumen more than the less 

 .refrangible half. Undigestible proteids are abundantly funned even in 

 the dark when sugar is present ; but in still greater quantities in the 

 light. In the blue half of the spectrum a larger quantity of undigestible 

 proteids is formed than in the yellow half. The energy of respiration 

 in leaves supplied with sugar is twice as great in the light as in the 

 dark. Tlie proportion between the carboa dioxide produced and the 

 nitrogen of the undigestible proteids is nearly constant. The experi- 

 ments were made on etiolated leaves of Vicia Faba. 



Formation of Proteids in the Dark.J — M. J. Goldberg states, 

 from observations made on the germination of wheat, that proteid sub- 

 stances are formed in the embryo in considerable quantities. Since 

 this phenomenon takes place at the close of the period of germination, 

 it is clear that the formation of proteids is not effected at the expense 

 of the decomposition of proteid substances which have passed by osmose 

 from the endosperm. 



Destruction of Chlorophyll by Oxydising Enzymes. § — Mr. A. F. 

 Woods, after recording the results of numerous interesting experiments, 

 thus sums up the evidence. Chlorophyll is rapidly destroyed by oxydis- 

 ing enzymes (oxydases and peroxydases) which are normally present, 

 though in small quantity, in many of the higher plants. Under condi- 

 tions at present ill understood, these enzymes become more active or 

 are produced in abnormally large quantities, and are then the cause of 

 variegation, and maladies such as the mosaic disease of tobacco, which 

 disorder was ascribed by Beijerinck to a living fluid contagium.j] 



The oxydase and pcroxydase may remain in the soil for months. The 

 peroxydase will diffuse slowly into an agar substratum, and may retain 

 its active properties for a long time in the dried condition. In the 

 presence of egg-albumen oxydase does not always give the guaiacum 

 .reaction. In aqueous solutions the oxydases are destroyed in five 

 minutes at 65°-70° C, and peroxydases at 80-85° C. 



* Bull. Herb. Boissier, vii. (1899) pp. 459-66. 



t In Russian, Warsaw, 1898. See Bot. Ceutralbl., lxxix. (1899), p. 193. Cf. this 

 Journal, 1899, p. 299. 



X Rev. Ge'n. de Bot. (Bonnier), xi. (1899) pp. 337-40 (1 fig.). 

 § Centralbl. Bakt. u. Par., 2" Abt., v. (1899) pp. 745-54. 

 Cf. this Journal, 1899, pp. 319-20. 



