BOTANY. 287 



The development of the periodic law, F. P. Yexaui.k (Easfon, Pa.: Chemical 

 Puh. Co., 1S9C, PI). .!JI, 2)ls. IS). 



The hygienic laboratory, H. B. Kexwood (Methods of bacterial research by 

 R. Iloyoe) (J'hiJa(lcl2>hia: J'. Blakiston, Son <>• Co., 180.}, pp.l7,491,fi(j!i.ll6).—k labo- 

 ratory manual of the analysis of v/ater, soil, air, gas, food, etc. 



Chemical experiments, general and analytical, R. P.Williams ( Hoaioii and Lon- 

 don : Ginn cf- Co., 1SD'>, pp. XV, 111, figs. 40). — Detailed directions are given for per- 

 forming experiments with 102 different elements — salts, acids, etc. The book con- 

 tains much information of a general nature relating to the performance of chemical 

 experiments. 



Notes on qualitative analysis, AV. P. Masox (Easton, Pa. : Chemical Pub. Co., 

 1896, pp. 50). — A laboratory manual. 



Chemistry for beginners, E. Haut {Easion, Pa. : Chemical Pub. Co., 1806, pp. 245, 

 figs. 62, pis. 2, 3d ed., revised and enlarged). 



BOTANY. 



Assimilatory inhibition in plants, A. J. Ewart {Jour. Linn. Soc. 

 Bot, 31\1896), No. 217, vp. 364-461).— The author lias given the results 

 of a iH'olouged series of experiments carried on under the direction of 

 Pfeffer, of Leipsic. The method adopted for determiniug oxygen evo- 

 lution was by the use of the Bacterium tcrmo of Cohn. The cultures 

 used were always under 2 weeks old in order to secure actively motile 

 forms. The agents studied were heat — dry and moist — cold, irrespira- 

 ble gases, ether, acids, alkalies, antipyrin, accumulation of assimilatory 

 products, and insolation. The age of the leaf cell or chlorophyll grain 

 at which assimilation begins was also studied. The experimental mate- 

 rial covers quite a range of ])lants representing phanerogams, mosses, 

 lichens, etc. 



The author's conclusions are as follows: 



"By the operation of a variety of agencies a condition of assimilatory arrest or 

 inhibition may be induced in living chlorophyllaceous cells and tissues. These are : 

 dry heat, moist heat, cold, desiccation, iiartial asjihyxiatiou, etherization, treatment 

 ■with acids, alkalies, and antipyrin, accumulation of the carbohydrate products of 

 assimilation, imniersalin very strong plasmoly tic solutions, and prolonged insolation. 



"The inability to assimilate is, if the cell remain living, only temporary, being 

 followed sooner or latei- by a more or less complete recovery of the power of 

 assimilation. 



'■'During the whole time in which the ]>ower of assimilation is absent the cell 

 continues to respire. By the direct effect of each particular agency, the res])iratory 

 activity may in some cases be but little affected (etherization, overaccumulatiou of 

 carbohydrates), in one case is increased (nu)ist heat), but in most is diminished 

 (cold, desiccation, immersion in strong plasniolytic solutions). The question, 

 whether or not an after effect may also be produced on respiration, does not sensibly 

 afifect the results obtained as regards assiniilatiim. If the inhibition of assimila- 

 tion experimentally produced be permanent the cell tinally dies and ceases to respire. 



"In tlie great majority of cases no visible change in the chlorophyll or the chloro- 

 phyll grain is associated with the stoppage of assimilation. In such cases assimila- 

 tory arrest probably originates in the plasmatic stroma of the chlorophyll corpuscle, 

 and maybe due to some breakage in the necessary vital connection between the 

 assimilatory pigment and the assimilatory plasma. 



