ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
757 
BOTANY. 
A. GENERAL, including 1 the Anatomy and Physiology 
of the Phanerogamia. 
a. Anatomy. 
(1) Cell-structure and Protoplasm. 
Structure of Living Protoplasm.* — Injections of vegetable and 
animal tissues with mercury have led M. Y. Fayod to the conclusion 
that protoplasm is not an emulsion, but a reticulate tissue composed 
of canaliculate and spiral fibrils, with hyaline walls capable of excessive 
swelling. The canaliculate fibrils, which have about the dimensions of 
Spirillum tenue, he terms spirofibrils ; they are probably themselves 
composed of still finer spiral fibrils, the spirosparts , and these are all 
twisted round a canaliculate axis ; they together constitute the hyalo- 
plasm of Hofmeister. The visible granular portion of the protoplasm, 
the only part which takes up staining under ordinary circumstances, is 
simply the contents of these canals ; it is the chromatin of Flemming, 
and is capable of motion within the canals. The very delicate mem- 
brane of the spirals he terms fibrolem. 
The primitive spirofibril probably increases in size and becomes 
canaliculate simply in consequence of the growth of the spirals which 
arise in its interior ; and in this way it becomes transformed into a 
spiral composed of spirosparts with an axial canal. The fibrous net- 
work which constitutes the greater part of the protoplasm resists the 
action of staining reagents, but there are various ways in which its 
existence can be shown. 
The nucleus, which is probably nothing but a knot of the last extra- 
cellular net, is formed by the junction of several bands of spirosparts 
which traverse it in different directions. The granular portion of the 
protoplasm disappears under the action of active oxygen, and this 
disappearance is accompanied by an excessive swelling of the protoplasm, 
of which only the hyaline substance remains. This hyaline substance 
appears to be an organic body very rich in oxygen, and its formation 
to be due to the oxidation which accompanies respiration. The cell- 
wall of plants possesses precisely the same structure as protoplasm ; it is 
simply protoplasm impregnated by cellulose. 
The above description applies especially to vegetable protoplasm ; 
but that of animals possesses essentially the same structure. 
Structure and Growth of the Cell-t — Dr. C. Acqua has come to the 
following conclusions on this subject, derived largely from observing the 
growth of pollen-grains. Those tubes which increase directly and 
without interruption present a homogeneous wall with no visible lacera- 
tions ; the cellulose probably becomes rapidly stretched, as soon as it is 
formed, the constitution of the wall being very soft at the moment of 
its formation and for a short time afterwards. But when a period of 
activity is followed by one of rest, during which the wall is becoming 
gradually thickened, then, as soon as growth recommences, the old layer 
* Rev. Gen. de Bot. (Bonnier) iii. (1891) pp. 1S3-228 (1 pi.). 
f Malpighia, v. (1891) pp. 3-39 (2 pis.). Cf. this Journal, 1890, p. 734. 
