22 GENERAL HISTOLOGY. 



plasm grows by accumulation of nutrient matter in the interior. 

 In inorganic matter the surface or outside is the newest or last 

 deposited, but in a bioplast the outside is oldest. In growth 

 there is also a movement of certain parts of the surface in a 

 definite direction. Dr. Beale says: "Bioplasm alone, of all 

 matter in the world, moves towards lifeless matter, incorporates 

 it with itself, and communicates to it in some way we do not 

 in the least understand, its own transcendently wonderful 

 properties." "The rootlets of the plant extend themselves in 

 the soil because the living matter at their extremities moves 

 onward from the point already reached. The tree grows up- 

 ward against gravity by virtue of the same living power of 

 bioplasm. In every bud, portions of this living matter tend to 

 move away from the spot where they were produced, and 

 stretch upwards or onwards in advance. No tissue of any 

 living animal could be formed unless portions of bioplasm 

 moved away from one another." 



4. Structural power. The formation of structures and or- 

 gans with reference to their special uses or functions is a strik- 

 ing example of the presence of intelligence in creation. In 

 some instances a simple mass of bioplasm suffices all the needs 

 of the living being, as in the protozoa. This unicellular mass 

 extemporizes arms or feet or stomach out of its jelly-like ma- 

 terial according to its needs. In most organisms, however, a 

 division of labor is the rule, and the bioplasm divides and sub- 

 divides so as to make up the entire organism, in which all the 

 bioplasts are coordinated so as to act in harmony. Each has 

 its appropriate place and function, and subserves the general 

 good, unless disturbed by some morbid agency. The proba- 

 bility that all cells are united by a network of bioplasmic 

 threads renders this easier understood. 



The manner in which bioplasm changes from structureless 

 jelly into formed material and structures is a generally neg- 

 lected part of histology. We distinguish several processes. 



(i) Interstitial deposits. Bubbles of air may form vacuoles,or 

 oil, pigment, etc., may occur in cells. Vacuoles may be so 

 numerous as to form the bioplasmic mass into a network. 

 According to Heitzman this takes place in every embryonic 



