ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 541 



substances obtained by tlie action of alkalies is phyllotaonin, thus called 

 by the author from its resemblance in colour and lustre to the eyes in a 

 peacock's tail. The action of anilin on chlorophyll is then described, 

 and the properties of a substance termed anllophyll are enumerated. 



The author concludes by discussing tlie chemical constitution and 

 functions of chlorophyll. It may be assumed that chloroiihyll is a kind 

 of lecithin, of which phyllocyanin forms as it were the nucleus, together 

 with an unknown acid and an unknown base ; and he brings forward the 

 hypothesis that the unknown acid may be carbonic acid. The presence 

 of a body having a chemical constitution such as that would, it is evident, 

 serve a useful purpose in the vegetable economy. Some remarks are 

 also made on the substances which accompany chlorojDhyll, and on the 

 chlorophyll of animals. 



Formation of Chlorophyll by Coniferae in the dark.* — Herr H. 



Molisch states that Gingko hiloba (Scilisburia adiantifolia) furnishes an 

 exception to the general rule that seedlings of conifers have the power 

 of forming clilurophyll even when completely excluded from light. Not 

 a trace could be detected in a considerable number of observations. 



Formation of Starch in the Leaves of Sedum spectabile.t — Prof. J. 

 Bohm adduces further evidence of his view of the incorrectness of the 

 assumption that, because starch is again rapidly formed in leaves from 

 which it has been removed by subjecting them to darkness, when again 

 exposed to the light in air containing carbon dioxide, that therefore the 

 starch then found in the chlorophyll-grains is a direct product of assimi- 

 lation. His experiments were made on the coriaceous leaves of Sedum 

 spectabile, and confirm his previous conclusion that when the starch has 

 been removed a large quantity of sugar still remains in the leaves^ which, 

 on fresh exposure to light, is converted into starch. 



Mode of occurrence of Tannin in Plants.^ — According to Herr H. 

 Moeller, tannin occurs in plants in two different forms: — (1) As an iron- 

 green solution in the cell-sap, commonly permeating the cell-w^all, as 

 also the nucleus and chlorojihyll-grains. With potassium bichromate 

 this tannin is precipitated in the form of an irregular amorphous 

 powder. (2) Much the most common form is that of a homogeneous 

 strongly refringent oily fluid, usually coloured blue by iron-salts. This 

 form can be especially well detected in leaves of Pelargonium by 

 Gardiner's reagent (ammonium molybdate). An examination was made 

 of leaves of a number of different plants, and the author concludes 

 from the concurrent presence of tannin and starch in the assimilating 

 cells, and the separate occurrence of each in the conducting tissue, 

 and especially from the large accumulation of tannin in spongy paren- 

 chyme, parenchyme-sheaths, and the conducting parenchyme of vascular 

 bundles, that the transference of the carbohydrates in the form of com- 

 pounds of tannin is highly probable. 



(3) Structure of Tissues. 



Assimilating Tissue and Periderm in leafless plants.§ — Sig. H, 

 Eoss has examined the structure and development of the assimilating 



* Oesterr. Bot. Zeitschr., xxxix. (1889) pp. 98-9. 



t Bot. Centralbl., xxxvii. (1889) pp. 193-201, 225-32. 



t Ber. Deutsch. Bot. Gesell., vi. (1888) General- Vers. -Heft, pp. Ixvi.-lxxxii. 



§ Nuov. Giorn. Bot. Ital., xxi. (1889) pp. 21.5-4.5 (1 pi.). 



1889. ■ 2 p 



