66 PHYSIOLOGY [Bot. Absts. 



solutions of this glucoside. The disturbing effect of agostemma saponin on the latter plants 

 was shown by the death and falling of the root hairs, the coralloid aspect of the radical, and 

 the decrease in the production of dry material. The fact that Agrostemma Githngo will grow 

 in solutions containing 1000 times more agrostemma saponin than species of plants that do 

 not produce this glucoside, indicates the immunization of Agrostemma Githago against its 

 glucoside. In like manner saponin had a toxic effect on Oenothera, but did not affect Sapo- 

 naria which produces this glucoside. Amygdalin was toxic and decreased the production of 

 dry material in Raphanus sativus, Vicia sativa, Vicia macrocarpa, and Polygonum. Vicianin 

 was not toxic for Vicia. Amygdalin was not absorbed nor used by the radish as a source of 

 nitrogen or carbon. Vicia was not permeable to amygdalin nor agrostemma saponin. Agro- 

 stemma Githago could not absorb nor use agrostemma saponin as a food. One is not justified 

 in concluding that glucosides play no role in the plant and are simply waste products, from 

 the fact that they cannot penetrate the roots. — Dean A. Pack. 



440. Htjlton-Frankel, Florence, Helene Barber, and Eleanore Pile. Studies on 

 synthetic mediums. I. Study of the characteristics of some bacteria on a simple synthetic 

 medium. Jour. Infect. Diseases 24:9-16. 1919. — A synthetic medium having the following 

 constituents, with water to make one liter: — ■ 



cc. cc. 



129.5 Molar H 3 P0 4 100.0 Molar KOH 



18.8 Molar CH 3 COOH 10.0. . .0.01 per cent Fe 2 Cl 8 



17.8 Molar NH 4 OH 10.0. . .0.01 per cent MgS0 4 



100.0 Molar NaOH 10.0. . .0.01 per cent CaCl 2 



A hydrogen-ion concentration of 10. — 7 . N is suitable for the growth of most saprophytic bac 

 teria and some facultative parasites. None of the characteristics of the organisms were lost 

 from growth on the synthetic medium. [See also next following Entry, 441.] — SelmanA. 

 Waksman. 



441. Htjlton-Frankel, Florence, and Helene Barber. Studies on synthetic mediums. 

 II. Sugar fermentations in synthetic mediums. Jour. Infect. Diseases 24: 17-18. 1919. 

 — The same formation of acid and gas, with very few exceptions, was obtained for a number of 

 bacteria by using different sugars in broth and in a synthetic medium, the composition of 

 which has been given. [See also next preceding Entry, 440.] The use of the synthetic 

 medium presents special advantages in routine field work. — Selman A. Waksman. 



442. Lloyd, Francis E. The origin and nature of the mucilage in the cacti and in certain 

 other plants. Amer. Jour. Bot. 6: 156-166. 1919. — The mucilage of Opuntia, of certain Mal- 

 vaceae, and of Astragalus gummifer was studied. The mucilage cells in Opuntia are scattered 

 through the cortical and medullary parenchyma, the exact distribution varying somewhat 

 with the species. They are almost entirely absent from the primary growing point, being 

 secondary in origin and arising first in the medulla and later in the cortex. They are first 

 recognizable by their large size. The walls, at first like those of the adjacent cells, soon 

 become thickened by the change of their inner zone from ordinary cellulose to hydrocellulose. 

 It is from this zone that the mucilage arises; and as the layer of mucilage swells it compresses 

 the protoplasm toward the center of the cell, except at the pits, where the wall is not hydro- 

 lyzed and where projections of the protoplasm remain in contact with it. A treatment of 

 tissue with anaesthetics caused an abundant oozing of mucilage, due to the fact that the par- 

 enchyma cells around the mucilage cells become asphyxiated and gave up their water into the 

 intercellular spaces, whence it was used in hydrating the mucilage cells. Starch is found in 

 the protoplasts of the mucilage cells, a fact which indicates that the protoplasts may remain 

 alive. The mucilage layer shows lamination, which the author believes to be due to varying 

 degrees of hydration or to a layering in the original cellulose wall. He brings forward evi- 

 dence that the mucilage is neither laid dtwn'as a secondary layer, nor secreted within the 

 protoplast or on its surface, but that it is strictly a development of the primary wall of the 



