PHYSIOLOGY OF CELL-DIVISION 393 



to each local diffusion-field would correspond an electrical field 

 in which particles would be polarized and fuse as above suggested. 

 I have pointed out in an earlier paper^^ that the positions adopted 

 by chromosomes (which are undoubtedly negative particles^^) 

 relatively to astral centers indicates that the latter also are 

 negatively charged ; and there is little doubt that within the 

 small distances concerned in cell-phenomena the relative posi- 

 tions of the different colloidal aggregates will be influenced 

 by the charges which they carry ;^^ in fact, many phenomena 

 of normal and abnormal mitosis indicate that chromosomes are 

 repelled from the centers of radiation. This is probably the 

 cause of the characteristic arrangement relatively to these areas."*" 

 The similarity in the staining properties of chromosomes and 

 astral centers also indicates that both carry negative charges. 

 Each centrosomal area thus represents a negative area, i.e., the 

 region of lowest potential in the local electrical field — corre- 

 sponding to the diffusion-field — centering at each active centro- 

 some. It is to be noted that if this conception is true, each 

 hemisphere of the cell at the metaphase stage of mitosis is under 



*' Amer. Journ. Physiol., 1905, vol. 15, p. 46. 



■'^ This is obvious to the student of colloid chemistry. Nucleoproteins, on 

 account of their acid properties, will be more negative, i.e., will have higher 

 isoelectric coefficients, than the majority of proteins. For example, according 

 to Michaelis, the isoelectric coefficient of a nucleoprotein from the pancreas is 

 3 X 10~^ as compared with values ranging from 2X10~^ to 2X10"'' for other pro- 

 teins (of. Hober, loc. cit., p. 330). The possibility of differentiating by means 

 of acid and basic dyes the different proteins in cells (chromatin, etc.), "after fixa- 

 tion with acid fixing fluids, depends in fact on this difference. The chromatin, 

 being a nucleoprotein, remains negative, and hence stainable by basic dyes, after 

 treatment with fluids which are sufficiently acid to render positive the charge 

 on all the other protein colloidal particles present. 



■•^ Cytological evidence confirms this point of view. Cf. Conklin's general 

 discussion of the mechanism of differentiation in The Anatomical Record. 1909, 

 vol. 3, p. 153; "the movements of substances within cells take place largely 

 through the instrumentality of the astral system of the mitotic figure, or of the 

 entering spermatozoon," etc. 



*^ See the experiments with magnetic models in my paper just cited (footnote 

 43). The chromosomes, previously to division, adopt positions of equilibrium 

 midway between adjacent astral centers; this behavior is most evident in multi- 

 polar mitoses; for some especially striking examples cf. Kostanecki's paper on 

 the parthenogenetic eggs of Mactra, Archiv fiir mikroskopische Anatomie, 1908, 

 vol. 72, plates 14 and 15. 



