290 SUMMARY OF CUKKENT RESEARCHES RELATING TO 



A new genus of plankton-diatoms is described, Botellus g. n., the 

 sausage-shaped cells of which are connected into long slightly wavy 

 chains. 



(2) Other Cell-contents (including: Secretions). 



Chlorophyllins and Metachlorophyllins.* — M. Tsvett finds in green 

 leaves a second chlorophyllin, besides the blue one already described. 

 In some plants the structure of the chlorojmyllins is modified, and they 

 form a group of substances to which the author gives the name 

 metachlorophyllins. To this class belong the beautiful green crystals 

 separated by Borodin, the " crystallisable chlorophyll " of Monteverde. 



Myrosin.f — Th. Bokorny finds this substance more widely distributed 

 in the vegetable kingdom than has hitherto been supposed. It is readily 

 recognised by giving off the odour of mustard in the presence of 

 potassium myronate and water. It was found in all Cruciferae examined 

 with the exception of Hesperis matronalis ; also in the carrot and parsley 

 among Umbellifera?, and species of Allium among Liliaceae. The ordinary 

 glucoside present is potassium myronate, with the exception of a few 

 (Jruciferse (e.g. Capsella bursa-pastoris), and of all plants outside that 

 order which contain myrosin. Myrosin is more resistant to morbific 

 agents than protoplasm. 



Digestive Secretion of Nepenthes.^ — The late M. Clautrian appears 

 to have set at rest the controversy respecting the digestive properties of 

 the secretion of the urns of Nepenthes, by a series of observations on 

 two species in their native habitat of Java, N. Sedeni and N. melamphora. 

 Although, owing to the comparative scarcity of small insects, no large 

 numbers are found in the urns, the bodies of those that are captured are 

 more or less completely digested, and not by the agency of microbes, 

 the presence of which was excluded in experiments made with sterilised 

 white of egg. The fluid, while in the urns, is neutral to reagents, but 

 shaking the urns, or introducing any foreign substance, renders it acid. 

 The zymase which performs the active part in the digestion must be 

 regarded as a pepsin rather than as a trypsin. 



Manna of the 01ive.§ — In a district in Algeria, M. Trabut finds an 

 exudation from olive-trees identical in chemical composition with the 

 manna of the ash. The exuding region is limited to the trunk and the 

 larger branches, where the phloem is completely liquefied by an organism 

 which is apparently a bacterium. It produces large cankers and turns 

 the wood black, but the production of fruit does not appear to be affected. 

 M. Trabut attributes the disease to a bacterium capable of living on the 

 cambium, which is brought by insects, probably grasshoppers. 



Excretion of Resin by the Leaves of Conifers. — Frau E. Schwa- 

 bach || defends herself from the objections taken by Tschirch to her 

 previous observations on this subject, and maintains, as the result of a 

 fresh series of experiments, that the drops in question are not a fatty 

 oil, but, as she has before asserted, are resin. 



* Comptes Rendus, cxxxii. (1901) pp. 149-50. Cf. this Journal, ante, p. 50. 

 t Chem. Ztg., 1900. See Bot. Centralbl , lxxxv. (1901) pp. 72, 73. 

 JvMe'm. Couron. Acad. r. Belgique, 1900. See Biol. Centralbl., xxi. (1901) p. 33. 

 Cf. this Journal, 1900, p. 479. § Comptes Rendus, cxxxii. (1901) pp. 225-6. 



|| Ber. Deutsch. Bot. Ges., xviii. (1900) pp. 417-21. Cf. this Journal, 1900, p. 214. 



