674 
Strassburger' s Theory of Generation. [November, 
framework is placed in a nuclear cavity tilled with the 
nuclear fluid and surrounded by the nuclear wall, which 
Strassburger regards as a membranous layer of the sur- 
rounding cytoplasm. This nuclear wall is internally in 
contadt with the windings of the nuclear framework, but he 
does not assume a diredt continuation of the cytoplasmic 
threads into the framework of the nucleus. The reciprocal 
adtion between the stationary nuclei and the cytoplasm is 
therefore merely dynamical, — i.e., it takes place without 
any transportation of matter. The nutriment which the 
young cell-nucleus requires after fission, to complement its 
mass, issues in a soluble state from the cytoplasm, and 
passes through the nuclear wall. When a division of the 
nucleus is to follow, the nuclear threads contradt and the 
microsomes coalesce with each other to form disk-shaped 
structures. A portion of the hyaloplasm also contributes to 
the formation of these disks. This portion of the hyalo- 
plasm which has passed into the microsome disks must 
have been present in the stationary cell-nucleus as an adtive 
nutrient plasm (nutritive nucleo-plasm). The residual por- 
tion of the hyaloplasm, which may still be detedted between 
the microsome disks, and which probably covers them with 
a delicate coating, is to be regarded as adtive, formative 
plasmas. This formative nucleo-hyaloplasm corresponds 
with Naegeli’s “ idioplasm,” — i.e., that part of the plasma 
which contains the hereditary tendencies. 
That we must also distinguish a nutritive and a formative 
hyaloplasm in the cytoplasm, where a firm texture is 
wanting, seems to follow from the processes in nuclear 
division. In this operation the cytoplasm penetrates into 
the nuclear cavity and produces the spindle-shaped fibres, 
which, when the separation of the filial nuclei has taken 
place, remain as connedtive threads, and allow of the forma- 
tion of the cell-plate from which the young partition-wall 
proceeds. Strassburger is inclined to regard these threads 
as the formative plasma of the cytoplasm. The equatorial 
parts of such threads remain as exceedingly delicate con- 
nedtive threads in the partition-wall, and maintain the 
connection between the single cytoplasts of the body of the 
plant. 
This formative cyto-hyaloplasm is, in a certain manner, 
idioplasm of the second order. It is to be regarded as the 
organ of adaptation, whilst the cell-nucleus represents the 
conservative principle in the organism. As far back as 1866 
Haeckel came to the conclusion that the nucleus mediates 
the transmission of the hereditary characters, whilst the 
