ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 773 



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



Composition of Chlorophyll.* — Prof. G. Arcangcli has repeated 

 Kraiis's fxperiracnts on chlorophyll with benzol, substituting fur tlie 

 benzol i)etroleuin benzine (henzina di pctroUo), and lias obtained similar 

 results. He concludes that clilorophyil is not a simple compound of two 

 substances, pure chlorophyll and xanthopliyll, but rather of a series 

 of green and a series of yellow pigments. 



Composition of Tannin.j — Commenting on Kraus's paper \ on the 

 physiology of tannin, Hcrr F. Reiuitzer states that under the name of 

 tannin a variety of substances are known in vegetable physiology, which 

 by no means exhibit similar chemical reactions. Thus the tannin of 

 oak-apples consists of a mixture of digallic acid and a glucoskle of 

 digallic acid. He suggests that the terms " tannins " and " tannic acids " 

 should be banished from vegetable physiology and vegetable chemistry. 



Sphero-crystals.§ — M. E. Rodier states that in Senecio vulgaris 

 sphero- crystals are produced in all the tissues of the stem, but princi- 

 pally in the cortical and medullary parenchyme. They are more 

 regularly spherical than those of inulin, but are arranged in nearly the 

 same manner in the cells. The colour of these bodies is a more or less 

 deep yellow. Anilin colours do not atfect spherocrystals ; but they 

 are easily soluble in cold, and still more readily in hot water. When 

 treated with ammonium oxalate, they are destroyed and replaced by 

 crystals of calcium oxalate, thus showing that spherocrystals contain 

 lime. By the application of various reagents it may be seen that sphero- 

 crystals are composed of a nucleus and an amorphous envelope, probably 

 of organic nature, separated by a crystalline cortex containing lime. 



Mucilage in the Endosperm of Leguminosse. |1 — Herr H. Nadelmann 

 states that the mucilage which is frequently f(jund in the cells of the 

 endosperm of Legumiuosfe, together with starch, aleurcne, and a fatty 

 oil, serves in the first place as a reserve food-material, the secondary 

 thickenings of the cell-wall which are comjiosed of celkilose being 

 absorbed and consumed in the process of germination. They are j)ro- 

 duced directly in the form of mucilage, and not as the result of a 

 modification of cellulose. The secondary thickenings, which often occur 

 also in the cells of the cotyledons, are, on the other hand, never com- 

 posed of mucilage. 



Starch in the Epiderm.^ — Prof. R. Pirotta finds, in several species 

 of Bhammis, considerable quantities of starch in the epidermal cells, 

 where it remains during the dead season, to be used up again on the 

 resumption of vegetative activity. The epiderm appears, therefore, to 

 act, in these cases, as a reservoir of starch for purposes of nutrition. 



Gluten in the Grain of Corn.** — According to Hcrr W. Johannsen, 

 gluten forms the main portion of the protoplasm in the amylaceous endo- 

 sperm-cells of wheat, and is not the result of the action of a ferment. 



* Malpighia, iii. (1889) pp. 3-14. 

 t Ber. Deutsch. Bot. Gesell., vii. (18S9) pp. 187-9G. 



X Cf. this Jourual, ante, p. 65-i. § Comptes Keiulus, cviii. (1889) pp. 90U-9. 

 11 Ber. Deutsch. Bot. Gesell., vii. (1889) pp. 248-55. 

 t Malpigliia, iii. (1889) pp. Cl-G. 



** Resume' du comptc-rendu d. travaux d. laboratoire d. Carltibcrg, ii. (ISSS) 

 pp. 199-208 (2 l:g9.). See Bot. Centralbl., xsxix. (1S89) p. 22. 



