LECTURE V.

Of Morbid Growths.-Of the Development, Growth, Nutrition, Decay, and Removal of Tissues.-Of Secretion. Of the Changes occurring in Living Matter.

MR. PRESIDENT AND GENTLEMEN,

WHEN we were considering the changes occurring in elementary parts during their growth, we saw that the proportion of the germinal matter to the formed material altered as the elementary parts increased in size. At first each consists of a mass of germinal matter, which is separated from its neighbours by a very thin layer of soft formed material. At this period of its life it may divide and subdivide, and several separate masses may be produced. Gradually, however, as each elementary part recedes from the vascular surface, the germinal matter ceases to divide and subdivide, although it still absorbs nutrient material and grows. Inanimate matter becomes germinal matter, and germinal matter becomes formed material. last, when the elementary parts are separated by a considerable stratum of younger ones from the nutrient surface, the formed material becomes harder and drier, and less permeable to moisture. The changes taking place in the germinal matter, now imprisoned in a firm thick layer of formed material, occur

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more slowly. It still lives, and slowly diminishes as its outer portions become converted into formed material. At last the conditions, under which it is placed, become so altered, that it dies, and perhaps becomes liquefied. A small space remains and marks its original situation.

The rate of multiplication of the masses of germinal matter seems to depend principally upon the quantity of nutrient material in contact with them. If this be very abundant they multiply very rapidly; while, if it be scanty, they increase in number very slowly. Rapid multiplication of the masses of germinal matter is constantly associated with the presence of a large amount of nutrient matter, and the production of a very small proportion of formed material.

Elementary parts which, in the normal state, become surrounded with a moderate thickness of formed material, may multiply very rapidly under conditions which render the production of formed material impossible.

Thus the young elementary parts (cells) of cuticle may grow more quickly than usual, and at last masses of germinal matter, destitute of formed material, growing and multiplying rapidly, may be produced. Pus corpuscles are thus formed; but before absolute pus is produced, there is always manifested a tendency to the development of such elementary parts as are met with in the normal state.

I have referred to the orderly arrangement which the elementary parts of all healthy tissues at every period of existence exhibit, and have shown that in certain morbid growths no such order exists, that in healthy organs there is a provision which prevents the different tissues, of which they are composed, from overstepping the limits which are assigned to them, while, in morbid growths, no such restrictions exist, and the power of infinite growth, which the germinal matter possesses, becomes apparent.

The difficulty of discussing many of these important questions is much increased by the very guarded manner in which

writers are in the habit of expressing themselves. The obscure language often made use of, and the complicated words, the definition of which is continually changing, not unfrequently render it a matter of great labour to the reader to form any accurate idea of the exact opinion which the author holds. In endeavouring to avoid these objections, by expressing myself simply, and without making use of the terms generally employed, I am well aware that my views will be fully exposed to the attacks of opponents, and any errors not being screened by ambiguity of expression, will be at once discovered; while I may also be open to the charge of being presumptuous, and shall thus, when in error, necessarily incur double censure.

Still, by pursuing this course, it is obvious that free discussion will be much facilitated, and the truth will, in all probability, sooner be discovered. To this everything should be made to give way, and personal interests must be absorbed in the general advantages which must result from efforts to facilitate the progress and diffusion of scientific truth.

An abnormal or morbid growth may originate in any tissue in the body. If it commences in a tissue of simple formation, it will retain, to a great extent, the character of this structure, but if it arise in one of the higher tissues it will soon become so modified that it would not be possible to determine its origin from its microscopical characters.

The character of a morbid growth will, therefore, in great measure, depend upon the tissue in which it originated. Not unfrequently it would be quite impossible to distinguish a section of a morbid growth from one of the healthy tissue in which it commenced. In other cases an important modification in the elementary parts will have taken place. The muscular fibre cells around the pylorus, and in other parts of the intestinal canal, sometimes increase enormously in number, leading to the formation of a firm unyielding tissue, which is almost as firm as fibro-cartilage (sometimes described as scirrhus of the pylorus).

As the contractile element increases, it loses its

contractile power, and the whole mass appears to be composed of a form of fibrous tissue, in which the separate fibres are very distinct, and arranged parallel to each other in concentric layers.

I shall be able to show you a specimen of a healthy structure in which the contractile elementary parts of organic muscle are seen, at the margin of the bundles, to shade into those of fibrous tissue. Up to a certain period the germinal matter of these might have produced organic muscle, but the contractile tissue not being produced, a lower form of tissue is as it were formed in its stead. Since such a transition may be demonstrated in the healthy state, we shall not be surprised at finding what amounts to a very exaggerated change, in disease. The elementary parts have multiplied enormously, but they have developed, not their characteristic contractile tissue, but a lower and simpler form of formed material, not possessing the peculiar endowments of the normal structure.

If the restrictions, under which a soft healthy tissue grows, be removed, a soft and often very rapidly growing structure results.

Those structures which in the healthy organism grow fastest, and pass most rapidly through the various stages of their existence, as would be supposed, give rise to the formation of the most terrible and uncontrollable of morbid growths. An irregular growth of a part of the secreting structure with the vessels, for instance, of the liver, kidney, mamma, sweat glands, &c., may lead to the formation of a very soft, spongy, and highly vascular growth, which will attain a very large size, and appropriate the nutrient material which properly belongs to other textures. After a time, perhaps, it reaches the surface of the body, and fatal hæmorrhage may take place from its superficial vessels. In many such morbid growths we can distinguish the elementary parts which have descended from those taking part in secretion, although they have become much modified, from the elementary parts which are connected with the vessels

prolonged into the structure. The former constitute the 'cells,' or 'cellular elements' of the morbid growth, and the latter with the vessels themselves, form the matrix,' or walls of the areolæ or spaces in which the cells lie.

When we consider what a very slight derangement of the elementary parts at an early period of development would infallibly lead to the suppression or exaggeration of normal structures, which are their direct lineal descendants, is it not wonderful that morbid growths (irregular growth of one or more tissues) or monstrosities (exaggeration or suppression of series of elementary parts from which numerous different tissues, entire organs, or limbs, are produced) are not of yet more frequent occurrence than they are?

Many healthy structures may be removed from the part of the body where they have been developed, to a distant part, and will nevertheless grow there. Skin, hair, teeth, and other tissues have been successfully transplanted, but perhaps the most interesting, and not the least useful, instance of this kind which could be adduced, is the transplantation of growing bone. M. Ollier has removed a portion of the periosteum from a bone, and planted it in a distant part of the body,-under the skin for instance, and bony tissue has been produced. The periosteum contains bone germs, which only require nutrient material to undergo development into ordinary bone. The practical surgeon will, of course, soon apply so important a discovery to the treatment of certain cases. Some textures retain their vitality after they have been separated from the parts where they grew, for a much longer period of time, and have a much greater power of resisting destructive agencies, than others.

In some of the lower animals, so active is the tendency to growth, and so strong the power of resisting what would seem to be adverse conditions, that mechanical separation into numerous parts serves but to increase the rapidity of the production of separate independent organisms.