ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
291 
two groups, thus forming a bipolar spindle. The mature spindle is 
characterised by the great length and crossing of the mantle-fibres. 
Spindle formation in the second division of the pollen-mother-cells is 
the same as in the first. No centrosomes were observed in any stage of 
the process. 
Chromatic Reduction in the Formation of the Pollen of Naias.* — 
M. L. Guignard points out that, in the chromatic reduction which takes 
place in sexual nuclei, the reduction in quantity as well as in number is 
secured bj the rapidity with which the two divisions succeed one another, 
allowing no time for the nuclei to enter into a state of rest and to in- 
crease the amount of chromatin. He has studied the process in the 
formation of the pollen of Naicis major , where the normal number of 
chromosomes in the vegetative nuclei is 12, and 6 in the sexual nuclei, 
the smallest number known in Phanerogams. The numerical reduction 
takes place only when the definite pollen-mother-cell commences to 
divide to form the four pollen-grains. During the first division of this 
mother-cell, each chromosome undergoes two longitudinal fissions, 
becoming quadruple. During the second division, the chromosomes 
already formed are merely uniformly distributed among the four pollen- 
nuclei ; there is no qualitative reduction. 
Nuclear Reduction and Function of Chromatin.f — Criticising 
H. Spencer’s theory of the fundamental principles of heredity, Prof. 
M. Hartog points out that the process of nuclear reduction involves no 
necessary reduction in the quantity of nuclear matter, but only in the 
number of the segments into which it is distributed. Hence it cannot 
have the physiological function ascribed to it as a “preparation for 
gametogenesis.” He suggests that it is the achromatic plasma or linin 
of the nucleus that is the transmitter of inherited properties, the chro- 
matin having a purely mechanical function in karyokinesis. 
(2) Other Cell-Contents (including- Secretions). 
Inulin.J — Dr. H. Fischer gives a detailed account of his researches 
on the occurrence of inulin in plants, its properties, microchemical 
reactions, &c. These latter present considerable difficulties, owing to 
the sphaerites or sphaerocrystals of inulin being seldom free from ad- 
mixture with other substances. 
From its osmotic properties, Fischer regards the size of the molecule 
of inulin as 300 times that of fructose, and 150 times [158 in text] that 
of saccharose, giving the formula 333 C 6 H 10 O 5 = C 1998 H 3 3 30 O 1665 . 
Inulin gives no reaction with iodine, and the mode of swelling by 
absorption of water is quite different from that of starch or gelatin. 
The sphaerites increase in volume on absorption of water, but do not 
pass gradually into the soluble condition, nor do they form paste ; on 
the contrary, they dissolve completely like crystals, or break up into 
granules. SphaBiites of inulin also exhibit a difference from those of 
other substances in their deep radial fissures, which are sometimes seen 
* Comptes Rendus, cxxviii. (1899) pp. 202-7. 
t Natural Science, xiii. (1898) pp. 115-20. 
X Beitr. z. Biol. d. Pflanzen (Cohn), viii. (1898) pp. 53-106. 
