C 
240 [Dec. 15, 
Cope. ] 
the cell theory, all the tissues of the animal organism or their bases, from 
first to last. That the ultimate or histological elements of all organs are 
produced originally by repetitive growth of simple nucleated cells, with 
various modifications of exactitude of repetition in the more complex, is 
taught by the cell theory. The formation of some of the tissues is as 
follows: 
Kirst Change—Formation of simple nucleated cells from homogeneous 
protoplasm or the cytoblastema. 
Second—Formation of new cells by division of nucleus and body of the 
old. 
Third—Formation of tissues by multiplication of cells with or without 
addition of intercellular cytoblastema. 
A, In connective tissue, by slight alteration of cells and addition of cy to- 
blastema. 
B. In blood, by addition of fluid cytoblastema (fibrin) to free cells 
(lymph corpuscles), which in higher animals (vertebrates) develop into 
blood-corpuscles by loss of membrane, and by cell development of nucleus. 
C. In muscles, by simple confluence of cells end to end, and mingling 
of contents (KOlliker). 
D. Of cartilage, by formation of cells in cytoblast which break up, 
their contents being added to cytoblast; this occuring several times, the 
result being an extensive cytoblast with few and small cells (Vogt). 
The process is here an attempt at development with only partial success, 
the result being a tissue of small vitality. 
Even in repair-nutrition recourse is had to the nucleated cell. For 
Cohnheim first showed that if the cornea of a frog’s eye be searified, re- 
pair is immediately set on foot by the transportation thither of white or 
lymph or nucleated corpuscles from the neighboring lymph heart. This 
he ascertained by introducing aniline dye into the latter. Repeated ex- 
periments have shown that this is the history in great part of the con- 
struction of new tissue in the adult man. 
Now, it is well known that the circulating fluid of the footus contains 
for a period only these nucleated cells as corpuscles, and that the lower 
vertebrates have a greater proportion of these corpuscles than the higher, 
whence probably the greater facility for repair or reconstruction of lost 
limbs or parts enjoyed by them. Theinvertebrates possess only nucleated 
blood corpuscles. 
C, Synrursis OF REPETITION. 
That growth force is capable of exhibiting great complexity of move- 
ment with increase in amount, will now be shown. That this quality 
of complication is one of its distinguishing features will appear plain. 
The simplest forms of life, as stated by Heckel, are simply homogene- 
ous drops of protoplasm (Protamoeba). These only grow by ordinary ac- 
cretion, and display a form of self division or reproduction which is the 
simplest possible; ¢. ¢., the bisection of the mass by contraction at op- 
posite points. 
