﻿I903J CURRENT LITERATURE jl 



of alkali is even more injurious than a slight excess of an acid ; (2) the tem- 

 perature limits for light emission are within those necessary for growth ; (3) 

 change of temperature, either sudden or gradual, is without effect on lumi- 

 nescence, i. e., does not stimulate ; (4) there is no luminescence at or below 

 o"; (5) exposures to temperatures above the growth maximum are highly 

 injurious to the power of light production, while exposure to very low tem- 

 peratures seems to serve as a stimulus to light production ; (6) Bacillus phos- 

 phorescens is capable of adapting itself to high temperatures, producing a 

 race capable of light production at 35°, which is 5^ above the normal maxi- 

 mum for luminescence ; (7) a certain degree of continued illumination is 

 without effect, and it is possible for the bacteria to live their entire lives in 

 the dark and yet emit a brilliant light; (8) ether acts as a narcotic, prevent- 

 ing luminescence, but not growth and multiplication ; (9) it is possible to 

 develop a race of bacteria so immune to the action of small amounts of ether 

 as to be still luminous in its presence; (10) peptone or related protein is 

 required for the nutrition of luminous bacteria ; (11) dextrose and certain of 

 the higher sugars maybe utilized advantageously by B. phosphorescens ; (12) 

 either sodium or magnesium is required for growth, and especially for light 

 production ; minimum, maximum, and optimum amounts of sodium are 

 observed for growth and luminescence; (13) potassium, ammonium, lithium, 

 rubidium, calcium, barium, and strontium cannot replace sodium (or magne- 

 sium). — J. M. C. 



Strasburger^s has recently published a very complete account of the 

 morphology and biology of Ceratophyllum submerstim, and has made this 

 work the occasion for some interesting and important remarks upon phylo- 

 geny. As is well known, the pollen is discharged and pollination takes place 

 under water. The anthers ripen in succession and an enormous quantity of 

 pollen is produced, so that, in spite of the inevitable loss, most of the ovules 

 produce seeds. The embryo sac shows nothing unusual in its structure. 

 Double fertilization was observed and the chromosomes, twelve in the gamet- 

 ophyte and twenty-four in the sporophyte, were counted. The formation of 

 the endosperm is peculiar. At the first division of the endosperm nucleus a 

 transverse wall is formed, dividing the sac into two chambers, of which the 

 one nearest the chalaza does not divide again ; the other divides, and here 

 again only the cell next the micropyle divides again. This method contin- 

 ues for a few divisions, and then walls are formed in three planes, giving 

 rise to a small-celled tissue near the embryo, and a filament of a single row 

 of cells at the chalazal end of the sac. In early stages the embryo is spheri- 

 cal, and there is no suspensor. At a later stage the embryo bears a striking 

 resemblance to that of Nelumbo which Lyon described as having but one 

 cotyledon and a lateral stem tip. Strasburger finds two cotyledons in Cera- 



3«Strasburger, E., Ein Beitrag zur Kenntniss von Ceraiophylhitn submersttm 

 und phylogenetische Erorterungen. Jahrb. Wiss. Bot. 37: 477-526. ph.g-ii. 1902. 



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