1881.] 



MICROSCOPICAL JOURNAL. 



given excellent results, without any 

 preliminary treatment. 



Cellulose dissolves quite readily in 

 an ammoniacal solution of cupric 

 oxide. 



The action of reagents upon the 

 cellulose-walls of cells, is often greatly 

 influenced by the changes which they 

 undergo during the processes of 

 growth. It is not the proper place 

 here to consider this subject, but it 

 will be fully discussed when we have 

 to study the growth of the cell-walls 

 more particularly. It is a matter of 

 great importance in the examination 

 of textile fabrics. 



Elder-pith and fibres of cotton 

 afford excellent specimens for the 

 study of cellulose. 



Protoplasm is the name which has 

 been given to the syrupy or gelatinous 

 portion of living cells. Young cells 

 are filled with it, but as they grow 

 older the sap begins to form, first ap- 

 pearing as cavities or vacuoles in the 

 protoplasm, soon the protoplasm 

 spreads over the inner face of the 

 cell-wall, leaving the more fluid sap 

 within. 



Often the nucleus of the cell is 

 supended in the centre by means of 

 threads of protoplasm, which extend 

 from the outer layer across the cavity 

 which is filled with the sap. This 

 arrangement is beautifully shown by 

 some species of Spirogyra^ and has 

 already been demonstrated before this 

 Society. The layer of protoplasm is of- 

 ten quite distinctly visible under the 

 microscope, as in the cells of Nitella, 

 Anacharis and Vallisfierta, but more 

 frequently it is very thin and delicate. 

 It can always be demonstrated by 

 treating the cells with dilute acids, 

 alkalies, or a solution of sugar in 

 water, which will cause the proto- 

 plasm to retract from the cell-wall. 



The exact composition of proto- 

 plasm is very difficult to determine ; 

 it is a constituent of every living cell 

 and its characters seem to be the 

 same in both the animal and the ve- 

 getable kingdoms. From the proto- 

 plasm the other cell-contents, chloro- 



phyl, cell-sap, starch grains, and the 

 cellulose-wall itself, are elaborated. 



The distinctive characters of pro- 

 toplasm are well shown in such plants 

 as Nitella and Anacharis, in which 

 the phenomenon of cyclosis is so dis- 

 tinctly visible. It appears as a semi- 

 fluid mass, constantly moving around 

 on the inner face of the cell-wall. 

 Certain other plants show a different 

 motion of the protoplasm, which is 

 known as circulation. In these plants 

 the movement of the protoplasm 

 takes place in the form of currents 

 running in various directions. Circu- 

 lation may be seen in CEthalium sep- 

 ticum. 



Protoplasm is often found in a free 

 or naked condition, in considerable 

 quantity, and we are, therefore, en- 

 abled to study it more advantageously 

 than would be possible if it could 

 not exist without a cell-wall. Many 

 of the algse propagate by means of 

 swarm-spores, which are spherical 

 masses of protoplasm colored with 

 chlorophyll, quite destitute of any 

 cellulose membrane. Then we have 

 the Amoeba, the white blood-cor- 

 puscle and the so-called Plasmodium 

 of certain fungi belonging to the 

 Myxomycetes, which manifest the phe- 

 nomena of extension, retraction and 

 growth, which are the distinguishing 

 characters of protoplasm. The Plas- 

 modium is a mass of protoplasm from 

 which the fungi develop ; it is com- 

 mon on rotting wood in moist situa- 

 tions, in swamps and along shores of 

 streams, where it forms gelatinous 

 masses of considerable extent. In 

 this the amoeboid movements of pro- 

 toplasm are well manifested. 



The CELL-NUCLEUS is a spherical or 

 ovoid, clear or granulous particle 

 which is often quite distinct. It may 

 be suspended in the middle of the 

 cell by means of protoplasmic threads, 

 stretching from the protoplasmic utri- 

 cle, as already mentioned, or it may 

 be imbedded in the layer of proto- 

 plasm, and be carried around with it 

 in the cyclosis. Sometimes the nu- 

 cleus is very large, as in certain cells 



