380 PHYSIOLOGY, CHEMISTRY AND MORPHOLOGY. 



question liberates energy in the form of lieat, electricity, etc. ; the sec- 

 ond embraces synthetic, anabolic, or restorative acts by which there 

 becomes accumulated in the tissues under the form of exi>losive or 

 reserve materials the force necessary for the functions that develop 

 or reestablish the dynamical and histological losses they have suft'ered. 



Living matter is, to use a comparison of Hering,' like a copper wire 

 immersed in a solution of sulphate of copper, which, when conductiug 

 an electric current, loses on the one hand a portion of its substance by 

 solution, on the other accumulates an additional amount of metal. 

 These antagonistic functions have within oiir organism a close correla- 

 tion, being united in an intimate solidarity from which results that 

 dynamic and material stability that gives to a tissue its mori)hological 

 character. This solidarity has, in my o[)inion, among its other control- 

 ling conditions, a very important chemical basis. - 



You know that exercise develops organs and tliat this fact is con- 

 firmed throughout the entire sphere of our functions. Thus it is that 

 muscles enlarge in consequence of rei)eated movements, that glands 

 increase in size when obliged to perform nnusual work, that in other 

 terms function develops the organ through which it acts. We here 

 enter upon a functional circle which might in logic be called a vicious 

 circle, but which gives admirable results from a teleological point of 

 view. 



In a word, while an organ develops by exerting its functions, this 

 very development makes it more and more capable of performing those 

 functions. This relation, universally recognized, finds its applicatidu 

 in the doctrine of evolution and helps much to explain to us those mar- 

 velous progressions and difl'erentiations of structure by Mhich amor- 

 phous protoplasm is transformed into a complex organism. But when 

 we say that an organ develops by executing its functions, or that func- 

 tion makes the organ, we content ourselves with enunciating a tact 

 without explaining tlie mechanism to Miiich it is due. Let us try, 

 however, to throw light on some of the conditions that determine the 

 above-mentioned relations between an organ and its function. 



We are able to determine with considerable accuracy the stiunilants 

 that cause an organ to act, and that these are found partly in the 

 environment of the organism, partly in the interstitial blastema that 

 surrounds the tissues, partly within the elements of the tissues. All 

 our activities may therefore be classed as reflex acts, pseudo-automatic 

 acts and automatic acts properly so called. We also know that the 

 processes of molecular destruction that form the chemical basis of our 

 functional acts are frequently followed by a corresponding and pro- 

 portional amount of work of restoration, but we are ignorant of the 

 nature of the internal impulses that cause the tissues to restore them- 



' Heriug. Zur Theorie der Vorgiinge in der lebeudigen Substanz, Prag, 1888. 

 -Fano. "De qiielques bases physiologiques de la peusce," Revue de philosoijhie 

 scientifique, VoL IX, page 193, 1890. 



