253 



When now the power of the cell volume C, is calculated, by 

 which the plasma volume D increases, we find for it 1.2 or ^/s. 

 We find 0.6 or ^/s for the power of the cell volume bj which the 

 nucleus volume /T increases proportionallj. On increase of the nerve 

 cell the plasma volume varies, therefore, proportionally as the square 

 of the nucleus volume. As Vö X Vi8=^^/i8 or 73, the plasma volume 

 appears to increase proportional to the third root of tlie body weight 

 or P'/«, and the nucleus volume proportional to the sixth root of 

 the body weight or P'/a. 



Thus it appears that only the plasma, which is directly connected 

 with the nerve fibre, in such a way that the axis cylinder passes 

 into it, has the said direct dynamic significance. The nucleus, which is 

 always separated from the plasma by a membrane, is directly concerned 

 only with the life of the cell and its intern mechanism. The nucleus, 

 in the common opinion, is the bearer of the hereditary properties 

 in the nervous system, and it regulates the constructive metabolism, 

 growth, and reproduction of the cell. 



But still this "strange" exponent ^/is is only partly accounted 

 for. Why does the volume of the nucleus K vary pioportional 

 to the sixth root of the body weight, i. e. to the square root of the 

 body length, }/ L, or K^ to L? 



This too I already discussed on that former occasion. The follow- 

 ing remarks may now be added. 



It has appeared chiefly from the then cited cytological researches 

 and studies by Gerassimow, Boveri and R. Hertwig that the volume 

 of the plasma depends on that of the nucleus: The relative size of 

 the nucleus is determined by a dynamic state of equilibrium between 

 the volume of the nuclear substance and the free surface of the cell, 

 i. e. of the plasma. Further that with such a constant ratio the rate 

 of cell division also remains constant. Now we actually see in the 

 largest, i.e. full-grown homologous ganglion cells, in every case com- 

 pared above, the volume of the nuclear substance increase in nearly 

 quite the same relation with the body weight as the free surface of 

 the cell, for P'k = P'k, and P'hsX'k = P^'ls.. It may, therefore, be 

 admitted that these cells are in such a dynamic state of equilibrium. 

 The volume of the nucleus increases, indeed, somewhat less than 

 exactly proportional with the surface of the cell (which would be 

 required for cell division), but in this condition of the cell it remains 

 in equilibrium with the general dynamic condition of the body. For 

 the metabolism of the cytoplasma increases in the same rate with 

 the increasing volume of the nuclear substance K, and consequently 

 the kinetic energy issuing from the nucleus proportionally to K*. 



