Causes of the hypertrophy of the vascular system in granular degeneration of the kidney / by Robert Saundby.

  • Saundby Robert, 1849-1918.
Date:
1876
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Licence: Public Domain Mark

Credit: Causes of the hypertrophy of the vascular system in granular degeneration of the kidney / by Robert Saundby. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    8 of tlie muscular apparatus cannot have favoured a large capillary development, so that the su])erhcial area of the vascular system is relatively sin'all. I think, therefore, that are not going further than the facts warrant, if we infer that we have here all those con- ditions likely to favour increased fulness of that system. Now, let us proceed to .the inquiry to which these • considerations were necessarily preliminary; that is, whether increased fulness of the vessels can be looked upon as the efficient cause of the hyper- trophy of the muscular walls of the heart and arterioles. Mr Herbert Spencer (Principles of Biology, vol. ii. p. 351, et scq.), in considering the development of muscular tissue, points out tliat contractility is a primitive property of protoplasm occurring amongst the lowest rhizopods, where no differentiation of structure has occurred. He says, it may be supposed that certain of their colloidal molecules have a tendency, under the influence of what we call a stimulus, to undergo an isomeric change, in which they occupy less space—a state of equilibrium from which, on the re- moval of the disturbing force, they tend to fall, so as to be again ready to undergo the change when the disturbance is renewed. He had before shown that it is probable that a molecule which has had its components re-arranged will tend to impress similar changes on neighbouring molecules, so as to cause isochronism in their re- spective molecular movements. “ A portion of undifferentiated tissue, containing a predominance of the colloid that contracts in changing, will, during each change, tend to form new mole- cules of its own type from the other colloids diffused through it: the tendency of these entangled colloids to fall into unity with those around them will be aided by every shock of isomeric trans- formation. Hence repeated contractions will further the growth of the contracting mass, and advance its differentiation and in- tegration. If, too, we remember that muscular colloid is made to contract by mechanical disturbance, aud that among mechanical disturbances one which will most readily affect it simultaneously throughout its whole mass is caused by stretching, we shall be considerably helped towards understanding how the contractile tissues are developed.” “ The formation of a contractile layer in the vascular system becomes comprehensible; each dilatation of a bloodvessel caused by a gush of blood will be followed by a con- striction ; the heart will pulsate violently, in proportion as it is violently distended; arteries will develop in power, as the stress upon them becomes greater.” Such being in all probability the manner in which muscle is developed by the direct equilibration of matter to external forces under primary conditions, it is not less probable that in the fully organized mammal a similar develop- ment occurs under like conditions. I have shown tiiat tlie walls of the vessels are exposed to an increased strain; I have shown that this strain is probably due to an increased fulness, the result of increased endosmotic action from the 11 aids taken into the ali-