24 GENERAL HISTOLOGY. 



cell or bioplast, so that a network is generally seen with en- 

 largements at the intersections. See Fig. I, PI. 2. Motile 

 contractions and relaxations in these enlargements he deems to 

 be the primary movement of living matter, communicating by 

 filaments from each particle to those nearest to it, and thus 

 throughout the body. 



(2) Fusion of contiguous material. Thus certain softened epi- 

 thelial cells on the surface of mucous membrane may become 

 fluid mucus, and thus, according to some, the matrix of carti- 

 lage is formed by cell union. 



(3) Gradual transformation toiuards ttie surface. In the skin, 

 the inner layer of cells, or stratum lucidem, are bioplasmic net- 

 works, united by fibrous threads the prickle cells, so called 

 but the external layers are gradually transformed into a sub- 

 stance analogous to horn, and in the epiderm, or outer layer, 

 there is no living matter left. Yet this effete layer serves for 

 protection. The formation of hair and nails proceeds upon 

 the same method. 



(4) Linear formation. As a living particle moves onward it 

 may leave behind a fibrous train which may remain alive or be 

 changed into permanent structure. The sheath and axis of 

 nerve fibrils and the fibrous network of voluntary muscle may 

 have been produced by a modification of this method. In 

 ganglionic nerve fibers from a frog's heart there is a spiral ar- 

 rangement showing that the constructing bioplasm had a move- 

 ment of rotation as well as of progression. Fig. 2, PI. 2. 



(5) Division of nuclear fibrils. Modern microscopy shows 

 the living matter in most cells to be a network, which is finer, 

 or more concentrated, in the nucleus. Previous to cell divi- 

 sion the nuclear fibers are subject to great changes. They 

 become wreathed and twisted so as to resemble a star ; they 

 then split asunder and form a double star, after which the cell 

 divides, one of the fibrous stars being in each cell. Fig. 3, PI. 

 2. This process is called Karyokinesis, and in this way a sin- 

 gle particle of bioplasm may be multiplied by myriads. 



(6) Molecular coalescence is a modification of ordinary solid 

 forms when inorganic particles are aggregated in the presence 

 of organic or living matter. Mr. Rainey and Professor Harding 



