216 EXPERIMENT STATION RECORD. 



largely conducted to determine the effect of centrifugal force on the 

 nucleus. The results obtained bear directly upon the specific gravity 

 of the various cell constituents, and especially those of the nucleus. 

 It is stated that there can be no doubt that the nucleolus is relatively 

 a very heavy body and that its specific weight is greater in the nuclei 

 of cells (l(>stined to great constructive activity. 



The destruction of chlorophyll by oxidizing enzyms, A. F. 

 Woods (Centhl. Bakt. n. Par., 2. Alt., o {1899). No. 22, jyp. 7J^5- 

 7oJf). — The author reports on a series of studies made on the relation 

 which exists between oxidizing enz3'ms and decoloration of leaves. 

 Oxidizing enzyms. both oxidase and peroxidase, were found plentiful, 

 and some of their characteristics are descrilied, together with notes on 

 their presence and effect on variegated maple, horse-chestnut, and a 

 number of other plants. A careful comparative investigation showed 

 that the intensity of the power of oxidase was inversely proportional 

 to the amount of chloroph3'll present, as judged h\ color. The per- 

 oxidase follows the same rule. 



The principal portion of the investigation was conducted with 

 tobacco, in which the so-called blanching or mosaic disease was exam- 

 ined with particular care. Peroxidase was alwa3^8 found in greater 

 quantity and twice as strong in the light-colored areas as in the green 

 ones, and where the chlorophyll had nearly disappeared, leaving albino 

 spots, the oxidase was twice as abundant as in the green of the same 

 leaf or the green of healthy leaves. The author claims that there is 

 no good reason for separating this disease of tobacco from true varie- 

 gation or albinism. He has been able to produce it at will, and as 

 3^et no organism has been isolated that proved to be the cause of 

 variegation. 



The conclusions of the author are that chlorophyll is rapidly 

 destroyed by the oxidizing enzyms, oxidase, and peroxidase. These 

 enzyms are normally present in small quantitv in many of the higher 

 plants, and under certain conditions (Mther become more active or are 

 produced in greater (piantitv, resulting in variegations and other forms 

 of disease. The active agents in producing the mosaic disease of 

 tobacco appear to be enzyms rather than the '•living Huid contagion"' 

 suggested ))y Beijerinck (E. S. R., 11, p. 1H7). The mosaic disease 

 may be produced at will, and the enzyms can remain in the soil unin- 

 jured for several months. In aqueous solutions the oxidases arc 

 d(\str()yed by 5 minutes' exposure to temperatures of 65 to 70" C, and 

 the i)eroxidases by 5 minutes' exposure to temperatures of 80 to 85° C. 



On the formation of proteids during the germination of wheat 

 in darkness, J. Goldbeiu; {Rcr. (u'l,. B<>f.. 11 {1899). Xo. 129. pp. 

 337-3Ji.0,fi(/. 1). — A considerable number of grains of wheat were ger- 

 minated in the dark, at temperatures ranging from 20 to 22.5°. At 

 intej'vals of 3, 8, and 14 days the author removed 60 of the plantlets 



