678 WEST OF SCOTLAND VETERINARY MEDICAL ASSOCIATION. 
blood (and that the blood is changed in its character no one 
denies), and deposited in various parts or places of the body, 
either in the connecting tissue, or in the outer surface of the 
coats of the small vessels, and there by its presence exciting, in 
some instances, sufficient action in the surrounding vessels to 
ensure a supply of fluid for its nourishment and growth by im¬ 
bibition ; in other instances, depending probably upon some 
peculiar condition of the blood at the time, setting up a large 
amount of inflammatory action, and rapidly increasing; its rate 
of development also being regulated by the suitability of the 
pabulum in which it may be deposited. Of all this I say I am 
perfectly convinced. 
Morbid products, simple and innocent in themselves, may, 
under peculiar circumstances, be converted into malignant and 
disease producing germs. 
Mode of Growth .—According to Virchow this goes on by 
proliferation of the cells of the connective tissues; but, if I am 
correct in my view, it goes on from either internal molecular 
growth, or by inducing the flow of an exudate from the surround¬ 
ing vessels, each successive portion of which degenerates into a 
substance similar to the primary one. In some instances the 
presence of blood-vessels has been demonstrated within tubercles, 
and doubtless the nourishment, in such cases, would be derived 
directly from these vessels. 
The growth of tubercle always progresses much more rapidly 
in the young than in the adult animal, inasmuch as in the 
latter the textures are much more perfectly organised and con¬ 
solidated, thus for a longer time resisting the influence of any 
element of change wdiich may be brought in contact with them; 
and, as Addison truly remarks (p. 190), “The anatomical struc¬ 
ture of the infant is, as we have shown, materially different from 
that of the adult; nutrition and growth are more energetic; all 
the tissues are imbued with active morphological agents. The 
blood circulates with greater rapidity, and the newborn sympathies 
of sentient elements are more alert/'’ 
Mode of Degeneration .—This is thought by some pathologists 
to be due to chemical changes within the mass, and as a conse^ 
quence that degeneration commences centrally, other pathologists 
are of opinion that degeneration commences peripherally, and is due 
to the action of the living tissues surrounding it; fluid from which 
is transuded which gradually breaks the mass down. Both these 
views are correct, for degeneration does not proceed similarly in 
every tubercular mass. In fatty degeneration we have the action 
commencing in the centre; in suppurative degeneration it com¬ 
mences peripherally; in the cheesy tubercle it will frequently be 
discovered, on making a section, that the centre of the mass is 
