756 © 
are less abnormal, vary less from these struc- 
tures, and more resemble either hypertrophy or 
euplastic deposits ; and they do mischief rather 
from their size and situation than from their 
intrinsic nature. Where the mode of growth 
is more peculiar, and more independent of that 
of the textures in which they arise, the resulting 
tumours are more abnormal in their nature and 
mode of developement; they approach in 
character to malignant diseases, acting inju- 
riously, not only by their bulk and position, 
but also by abstracting the nourishment of the 
body, and tending to supersede the natural 
structures.”’* 
Among the malignant growths, too, there 
are various shades or degrees of malignancy ; 
one or more of the characters just now assigned 
to them being either absent or imperfectly de- 
veloped. Thus there are certain growths which 
have a tendency to spread through the system, 
and even to propagate themselves from one 
individual to another, and which agree with 
true malignant growths in being composed, 
like them, of cells having a tendency to rapid 
multiplication, but which yet exert no serious 
influence upon the general constitutional state, 
and which cannot, therefore, be properly termed 
malignant: such are molluscum and porrigo 
Javosa. And in other instances we meet with 
large tumours, producing a very injurious effect 
upon the surrounding textures, and exerting a 
very serious influence upon the system at large ; 
the malignancy of which, however, is doubtful, 
because they show no tendency to reappear in 
other parts of the body. The origin of all these 
growths is involved in great obscurity; but 
there does not appear to the writer to be any- 
thing so specific in their character as to require 
the supposition that their germs are introduced 
into the body from without. It is true that 
when they have once established themselves 
they may be propagated by inoculation, which 
transplants some of the cells or cell-germs into 
a new locality; and the appearance of the dis- 
ease in parts of the same body distant from 
those which were first affected, is probably due 
to the diffusion of the germs by the current of 
the circulation. But this power of reproduc- 
tion is by no means limited to malignant 
growths, since it belongs to all cells at a cer- 
tain stage of their developement. And, as Dr. 
W. Budd + has remarked, the causes which 
have been supposed to induce cancer are not 
such as can, in any intelligible way, favour the 
introduction of germs from without the body. 
Thus in chimney-sweeps and others the conti- 
bued application of soot has been observed to 
be followed by the occurrence of cancer in the 
scrotum in such a number of cases, as to justify 
the inference that it has been the exciting cause ; 
and the often-repeated contact of a tobacco-pipe 
with the lip has also been considered a cause 
of cancer of that part. But neither of these 
causes can in any conceivable way promote the 
developement of cancer from extmnsic germs. 
We are quite in the’dark, however, as to the 
be Williams’s Principles of Medicine, § 574. 
+ Lancet, May 28, 1842, 
NUTRITION. 
mode in which any perversion of the ordinary 
nutritive processes arising from external irrita- 
tion of whatever kind, can give rise to struc- 
tures so peculiar in their nature and history as 
are the various forms of cancerous growths. 
For a detailed account of their characters as 
unveiled by recent microscopic the 
reader must seek elsewhere ; since all thatwe 
can here attempt is to give a general idea of their 
liar nature. (See a Morbid.) — 
e greater part of every true malignant 
is Sale up of cells, which, instead of under- — 
going transformation into other kinds of tissue, — 
continue in their original state, and enjoy the — 
ase of rapid multiplication. In the harder 
rms of cancer the masses of cells are traversed — 
by bands of solid fibrous texture, and such are 
of slow growth, and may remain with but little © 
change for many years, apparently because the 
pressure to which they are subj prevents 
their rapid increase. But the softer forms ar f 
‘composed almost entirely of cells, and th 
of the most rapidly multiplying character ; so 
that, in the rapidity with which they shoot up, 
they remind us of the vegetable fungi. Now 
the influence of either of these forms of morbid 
growth upon the constitution is very decided, 
and distinguishes them from non-malignam 
structures ; but this is more evident, the mor 
time is afforded for the manifestation of thei 
effects. It is evident even from the appearance: 
of the subject of them that the blood must b 
in a very depraved state, for there is a peculi 
dirty sallowness about the complexion whi¢ 
is seen in no other disease; the emaciatic 
reaches a point unequalled under any oth 
circumstances ; and accidental injuries w 
may occur during the progress of the mala 
are but very imperfectly repaired. In their ¢ 
leterious effects upon the c of the circ 
lating fluid, therefore, we may not impropel 
compare cancer-cells with pus-globules. 
General summary.—From what has b 
Stated it appears evident, that the process 
nutrition essentially consists in the growth 
the individual cells composing the fabric; ; 
that these derive their support from the orgs 
compounds with which they are supplie 
the blood, just as the cells composing the: 
plest plants derive theirs from the inor 
elements which surround them. And as 
rent species of the latter select and cor 
these in such modes and proportions as_ 
rise to organisms of very diversified form 
properties, so is it easily intelligible # 
different parts of the fabric of the highe 
mals, whether normal or 
exercise a similar selective power, in re 
the materials with which the blood st 
them. The structure composing every $ 
portion of the body has what may be 
a special or elective affinity for some pal 
constituents of the blood; causing it to; 
from that fluid and to convert into it 
substance certain of its elements: and 
exercised not only in regard to the norm: 
stituents of the blood, but also towards 1 
matters which may be circulating wit 
the causes which enable the cells of : 
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AULIOTI: a % 
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