Organic dependence and disease : their origin and significance / by John M. Clarke.

  • Clarke, John Mason, 1857-1925.
Date:
1921
Catalogue details

Licence: In copyright

Credit: Organic dependence and disease : their origin and significance / by John M. Clarke. Source: Wellcome Collection.

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    PROTECT IV E COVERING A BASIC1 FACTOR IN DEPENDENCE A knight in armor is a protected fighter and by his pro- tection increase's Ids viability. A man “on Ids own,” who flights with his “dukes,” risks his viability lad nevertheless increases his physical vigor and exalts his bodily prowess. A recent writer on the morale of our army in France brings out the fact that a man who could defend himself with Ids fists made a better soldier than the one who depended alone on the weapon he carried in his hand. Nature has given to a large part of the animal world one or the other of two solid supports for the soft organs and Gosh of the body; an inside skeleton, like that on which our own soft anatomy is hung, or an outside skeleton or shell, to which we may here give special attention. I have used the expression, nature has given, meaning that the neces- sity of support to the body having early shown itself, such supports developed in response to external impacts and internal stresses; the historical course of development of these calcareous supports makes the fact sufficiently obvi- ous that they are a determined sequence and not a chemical reaction or a casual device. A rhizopod, a speck of soft protoplasm with the mar- vellous special function of eliminating the silica from its solution in the sea, exudes this mineral matter in the form of an outside shell of wondrous delicacy and sym- metry. The unprotected soft tissue in the primitive ances- try of all the great tribe of the Mollusca or shell-fish, tossed haphazard on the sea bottom and hopeless against attack except through concealment or powers of rapid self-propul- sion, acquires the special function of eliminating from the sea the salts of lime, carbonate or phosphate, and with them builds up its outside shell. We have just noticed that even toda\ the young of such hard-shelled mollusks, in stages when their shells are but beginning to grow, are free swim-