﻿^903] CURRENT LITERATURE 



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believe that amoeba could successfully attack a living cell, and as he found 

 for each amoeba present a cell of the coenobium absent and the amoeba 

 usually occupying the place of the missing cell, he concluded that the cell 

 was transformed into an amoeba. A careful examination of the literature of 

 a subject often changes a discovery into a confirmatory account. — W. J. G, 



Land. 



Benecke publishes the following results of experiments on brood-buds 

 of Lmiularia crjiciata,^^ Chemical stimulation is necessary for normal devel- 

 opment; no variations of temperature or light will produce normal thaJli or 

 rhizoids in pure water ; the small amount of mineral water dissolved from 

 certain kinds of glass is sufficient, however. In such very weak solutions 

 light is necessary for the development of rhizoids; one per cent, solutions of 

 certain salts produce them either in light or darkness. Complete nutrient 

 solutions produce large thalli and short rhizoids; lack of nitrates the reverse; 



( lack of phosphates intermediate; lack of potassium a general retardation; lack 



of calcium stunting, especially of rhizoids; magnesium and sulfates make little 

 difference ; surplus iron inhibits growth of rhizoids. The effect upon rhizoids 

 is the resultant between the direct influence upon them and the indirect influ- 

 ence through the thallus. The thallus is smaller and the rhizoids fewer, but 

 usually longer in darkness. Immersed buds show " water-etiolation ;'* rhi- 

 zoids in a moist chamber show "air-etiolation;" in solutions poor in nitrates, 



j *' etiolation due to nitrogen-hunger." This last idea is supported by experi- 



ments of Benecke and others with the rhizoids of Riccia fluitans zn^ roots of 

 higher plants. — L. M. Snow. 



Cytologists will find in a paper by Hacker'^ an excellent discussion of 

 the individuality of the parental chromatin. After a critical review of the 

 literature, a large part of which has been contributed by himself, the follow- 

 ing conclusion is stated : The autonomy of the paternal and maternal halves 

 of the nuclei can be traced in copepods from the fertilized ^^% through the 

 life Cycle to the ^^^ and sperm mother cells. During the maturation of the 

 ^^% in Cyclops there is a rearrangement of the chromatin elements so that 

 the t^^g cell contains, in equal measure, elements from the grandfather and 

 grandmother. Connected with this rearrangement is a pairing of the grand- 

 father and grandmother chromosomes. It may be suggested with great prob- 

 ability that this autonomy is of wide, if not general, distribution in plants and 

 animals. The nuclear stages in which the idiomeres (partial nuclei) and gono- 

 meres (double nuclei) appear are closely related. The second part of the paper 

 deals with the nature of fertilization, mixed inheritance, affinity of chromo- 



■ 



^^ Benecke, W., Ueber die Keimung der Brutknospen von Lunularia cruciata. 

 ■Bot. Zeit. 6i^: 19-46. fii^s. 6, 1903. 



'7 Hacker, Valentin, Ueber das Schicksal der elterlichen und grosselterlichen 

 Kernantheile. Morphologische Beitrage zum Ausbau der Vererbungslehre. Jena. 

 Zeit. Naturwiss. 37: 2g^-'i9^. figs. 16, pis. 1-4. 1902. 



