ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 361 



Tyree " marble " and similar rocks, due, as the authors believe, to 

 decretion of the original silicate. As regards the calcitic layer con- 

 taining the " intermediate skeleton " in typical specimens of Eozoon, 

 the calcite composing this part is "plainly a replacement pseudo- 

 morph after serpentine." This explanation would account for the 

 alleged cases of " chambers " and " canal system " preserved in 

 calcite. 



BOTANY. 



A. GENERAL, including Embryology and Histology of the 

 Phaner o gamia. 



Chemical Difference between Dead and Living Protoplasm. — 

 In the paper by Dr. O. Loew and T. Bokorny, noticed under the 

 above heading at vol. i. (1881), pp. 906-7, it should have been stated 

 in the description of the method employed for producing the reduction 

 of silver by the protoplasm, that the silver nitrate solution must be 

 used in an alkaline condition, produced by the addition of ammonia. 

 Similarly, to obtain reactions vt'ith gold chloride and platinum 

 chloride respectively, the previous addition of caustic soda to the 

 solution of the salt is necessary. 



Dr. Loew describes the preparation of the silver solution as 

 follows: — (a) Prepare a 1 per cent, solution of nitrate of silver; 

 (h) mix 13 cc. of a solution of potash (1-33 sp. gr.) with 10 cc. of 

 caustic ammonia (1*96 sp. gr.), and dilute with water to 100 cc. 

 Mix 1 cc. of each of (a) and (b) and dilute the 2 cc. to 1 litre imme- 

 diately before use. 



Occurrence of Aldehydes in Chlorophyllaceous Plants.* — J. 

 Eeinke and Kriitschmar assert the presence of volatile reducing 

 substances in all the chlorophyllaceous groups of plants ; in algae, 

 lichens, mosses, ferns, conifers, and angiosperms ; while they are 

 absent from fungi and etiolated seedlings of flowering plants. Their 

 occurrence appears therefore to be connected with the presence of 

 chlorophyll, though they may spread to the parts which do not 

 contain this substance. The authors determined the presence of two 

 such substances of different reducing powers. From the powerful 

 reducing properties, it is inferred that these substances belong to 

 the class of aldehydes; and their power of reducing a neutral 

 silver solution in the cold appears to identify them with formic 

 aldehyde. If this should not be confirmed, they may possibly be 

 identical with acetol or with some other " ceton-alcohol." 



Organ not hitherto described in the Vegetable Embryo.f — 

 G. Briosi describes a part of the embryo which he finds in some 

 plants, and which has hitherto escaped attention. If the exalbumiuous 



* Berichte deutsch. chem Ges., xiv. (1881) p. 2144. See Bot. Ztg., xl. (1SS2) 

 p. 57. 



t Gr. Briosi, Sopra un organo finora non avvertito di alcuiii embrioui vegetali. 

 15 pp. (3 pis.) Rome, 1882. 



Ser. 2.— Vol. II. 2 B 



