98 
Dr. BealEj on the so-called 
fied, if not entirely abandoned. So far, however, no observer 
has brought forward facts opposed to it, although some have 
expressed their dissent in general terms, which is not to be 
wondered at. 
Now, cartilage is probably the tissue which an opponent 
would select as the one most likely to afford evidence against 
me ; and I propose, therefore, to discuss the minute structure 
of this particular tissue, and shall endeavour to draw conclu- 
sions as to the manner in which it is developed and grows. 
The general structure of cartilage is represented in PI. VIII, 
fig. 1, from the temporal bone of an adult frog prior to ossi- 
fication. 
Structure of Embryonic Cartilage. 
All cartilage, at an early period of development, consists of 
masses of germinal matter imbedded in or surrounded with 
a soft-formed material. The masses of germinal matter, 
which are at first very close together, multiply by division. 
(Figs. 1, 5.) Now, as development advances, the masses 
of germinal matter become separated from each other by 
gradually increasing distances, or, as I would say, the formed 
material gradually accumulates between them as it continues 
to be produced, but more and more slowly, upon the surface 
of each mass. (Figs. 5, 6, 7, B.)"^ 
If the young cartilage be broken up, portions of the formed 
material are seen to be continuous with the germinal matter 
(fig. 2) ; and in specimens coloured with carmine we see, first, 
the smooth and very finely granular and transparent ' matrix' 
or ^formed material' colourless ; next, a layer faintly coloured; 
and lastly, it is observed that the intensity of the colour in- 
creases as the matter situated more or less centrally is ap- 
proached. From this I argue that there is a gradual growth 
and transformation proceeding from within outwards ; and 
as it is a fact that my colouring matter passes through all the 
outer layers, and is deposited in greatest quantity in the cen- 
tral part which is at the greatest distance from the solution, 
it seems only reasonable to infer that pabulum takes the same 
course during life. These points are shown in figs. 1 and 2. 
But the development of cartilage can be studied in the 
fully formed tissue as well as in the embryo^ for up to a certain 
period of life many of the cartilages are continually growing. 
Indeed, if growth did not occur, the cartilage would diminish 
in extent, because, as age advances, the formed material 
* Preparations illustrating the facts stated were passed round at the 
meeting. 
