114 Transactions. — Miscellaneous. 



between the cell-wall and tlie green endochrome. In the clear space at 

 each end is a black spot which, under sufficient magnifying power, is 

 resolved into a number of excessively minute cells, each with a dark circum- 

 ference and clear centre. These cells are in a state of continual motion, in 

 and out amongst each other, changing their relative position, and circling 

 round and round. Frequently cells leave the terminal group, pass down 

 between the cell-wall and the endochrome-wall for a certain distance ; then, 

 altering their course, return in the opposite channel, and rejoin their friends 

 at the extremity of the frond, — the whole diorama forming a scene of 

 wonderful activity and exquisite beauty. So that we may fairly infer that 

 the physical difference between the animal and vegetable living cell is only 

 one of mechanism. But these living cells have other functions to perform 

 than mere mechanical motion, whether that motion be external or internal. 

 They have to perform certain vital acts — they have to grow, and they have 

 to multiply ; and their growth is carried on in a manner peculiar to the 

 organic kingdom. It is not a mere increase in size, like the growth of a 

 crystal which, as you know, may be suspended in a solution of the substance 

 of which itself is composed, and, as evaporation takes place, becomes 

 enlarged simply by the deposition of the matter, which can no longer remain 

 in solution, on its exterior, Livuig beings, on the contrary, grow by the 

 admission of matter (the chemical composition of which is often quite 

 different from themselves) to their interior, where it first undergoes a pro- 

 cess of chemical change by which it is assimilated to their own composition, 

 and is then incorporated into the living bodies themselves. 



The multiplication of these cells occurs in at least three different ways. 

 First, as may be seen in any fermenting solution, the yeast particles in- 

 crease by gemmation or budding, A full-grown cell may be seen with a 

 much smaller one sprouting as it were from it, and thus strings of several 

 cells are sometimes formed. These secondary cells having attained a cer- 

 tain growth, detach themselves, and in their turn carry on the process. 

 Second, by the process of cell division, A constriction appears in a cell, 

 and gradually becomes deeper, until eventually it divides the cell into two, 

 which become independent bodies. Third, by the division of the proto- 

 plasm of the parent cell into numerous secondary cells ; the parent cell 

 then bursting, the secondary cells become free, to go in their turn through 

 the same process. By one or other of these methods all animal and vege» 

 table growth takes place, and may be watched, not only in those living 

 beings which consist of a single protoplasm cell, but also in the growing 

 parts — the seeds, roots, and tender sprouts — of the higher plants, and in 

 the eggs of animals. 



So far you will perhaps have noticed that no distinction has been drawn 



