ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 235 



or even by long exposure to light ; in this condition they are insoluble 

 in alcohol, ether, and dilute alkaline solutions. 



The resinous substance which covers the surface of leaves soluble 

 in alcohol becomes absolutely insoluble, without changing its com- 

 position, by heating above 100° C. 



The analysis of the potassa, lime, and baryta salts of these two 

 acids gives the following results: — Stearocutic acid, C 75 '2, H 11 '7, 

 O 13 '1 per cent., or CeoHggOg; Oleocutic acid, C 65-6, H 9-4:, 

 O 25 per cent., or C28H24O8. Neglecting the small quantities of 

 lime and of calcium phosphate in the cuticle, we may say that it is 

 composed of five equivalents of oleocutic and one of stearocutic 

 acid; giving nearly the percentage composition, C 68*2, H 10, 

 21-8. 



Cutose occurs not only on the surface of leaves, flowers, fruits, and 

 stems ; it penetrates also into the interior of organs, and may 

 constitute as much as 43 per cent, of bark ; it is found also in fibro- 

 vascular bundles. 



In the process of maceration by which the fibrovascular bundles 

 are separated in hemp and flax, a fermentation is set up accompanied 

 by the presence of amylobacteria, which dissolve the cellulose- tissue 

 that holds the fibres together. The fermentation is of the kind kno^vn 

 as pectic fermentation, and results from the development out of 

 pectose of metapectic acid which is soluble in water. The authors 

 suggest that in the important processes of the preparation of flax and 

 hemp fibre, the ordinary mode of maceration may be replaced by a 

 chemical maceration (rouissage chimiqae), by which the pectose or 

 calcium pectate may be converted into metapectic acid, and the cutose 

 aud vasculose into resinous acids, and the fibrovascular bundles thus 

 liberated by means of caustic or carbonated alkalies much more 

 economically and advantageously than by the method at present 

 employed. 



The subsequent process of bleaching the fibres of flax and hemp 

 depends on the removal of the last traces of cutose, vasculose, and 

 pectose. The last may be advantageously eliminated by means of an 

 alkaline carbonate; the latter by some oxidizing agent such as 

 chlorine, the hypochlorites, oxygenated water, nitric acid, or potas- 

 sium manganate, and then washing with an alkaline solution to remove 

 the resins formed as the result of the oxidation. This is identical in 

 principle with the ordinary process of bleaching. 



The perfectly pure fibres thus separated are composed of cellulose 

 and paracellulose, as is shown by their chemical reactions. They may 

 be obtained from flax and hemp by the methods described, of as great 

 fineness as threads of silk, and they take pigments as well. The 

 authors propose for the substance the name " fibrisoie." 



Structure of Leaves in Relation to Nyctitropism.* — In this 

 abstract D. D. Cunningham discusses the " relation of particular 

 structural features in certain leaves to the phenomena of nyctitropism, 

 and movements incident on stimulation by concussion." The con- 



* Proc. Eoy. SoC; xxxiv. (1882) pp. 268-72. 



