FIBRE-CELLS, ETC. 127 
It had a gray and translucent appearance, exhibited no elas- 
ticity, and when examined with the microscope, presented no 
trace of its future structure. A gray cord, indistinctly marked 
with longitudinal fibres, was seen, in which a great many 
cell-nuclei might be recognized. I did not prosecute any fur- 
ther researches, as the presence of the nuclei was sufficient 
proof that there was nothing essentially different in the type 
of its formation. 
On casting a retrospective glance over the class of fibre- 
cells which we have just been considering, we find that it 
forms a very natural and somewhat strictly defined group 
amongst the tissues. The tissues comprised in it are generated 
from nucleated cells, which are transformed into fasciculi of 
fibres by elongation, in the first place, and by the splitting of 
the bodies of the cells themselves into separate fibres at a sub- 
sequent period. The fundamental phenomenon previously 
described at page 39 is distinctly presented in the formation 
of these cells; a structureless, gelatiniform mass, the cytoblas- 
tema, is first present, and lies outside the cells already formed. 
The cells are developed in this, the nucleus being, in all pro- 
bability, the earliest formation. The growth of the cells 
proceeds, and they become transformed into fibres in the 
manner described. The quantity of the cytoblastema con- 
tinually diminishes in proportion to the cells or fibres which 
are forming, but probably part of it remains persistent be- 
tween the fibres throughout the whole of life; in the mature 
condition, however, it exists in greater quantity in areolar than 
in fibrous or elastic tissue. 
The mode of generation teaches us which parts of these 
tissues correspond to the constituents of those hitherto treated 
of. The elementary cells of areolar tissue, before undergoing 
change, correspond morphologically with the cartilage and 
epithelium-cells, the mucus-corpuscles, &c.; and as a fasciculus 
of fibres is generated from each cell of areolar tissue, a whole 
fasciculus of fibres of areolar tissue accordingly corresponds to 
what was an individual cartilage- or epithelium-cell, in the pre- 
vious classes. The structureless cytoblastema between the 
fibres of areolar tissue corresponds, however, to the firm inter- 
cellular substance, forming the principal mass of most cartilages, 
