TRANSACTIONS OF SECTION D. 613 



bad before us, namely, tbat it is a constantly recurring alternation of opposite and 

 complementary states, that of activity or discbarge, that of rest or restitution. 



Is it so or is it not? In the minds of most physiologists the distinction 

 between the phenomena of dischar^re and the phenomena of restitution (L'r/iolu7i</) 

 is fundamental, but bej-ond tliis, unanimity ceases. Two distinguished men, oim 

 in Germany and one in England, I refer to Prolessar Ilering and J)r. Gaskell, have 

 taken, on independent grounds, a different view to the one above suggested, 

 according to which life consists not of alternations between rest and activity, 

 charge and discharge, loading and exploding, but between two kinds of activity, 

 two kinds of explosion, which ditler only in the direction in Avhich they act, in the 

 circumstance that they are tintagonistic to each other. 



Now when we compare the two processes of rest, which as regards living 

 matter means restitution, and discharge which means action, with each other, they 

 may further be distinguished in this respect, that, whereas restitution is 

 autonomic, i.e. goes on continuously like the administrative functions of a well- 

 ordered community, the other is occasional, i.e., takes place only at the suggestion 

 of external intiuences; that, in other words, the contrast between action and 

 rest is (in relation to protoplasm) essentially the same as between waking aud 

 sleeping. 



It is in accordance with this analogy between the alternation of waking and 

 sleeping of the whole organism, and the corresponding alternation of restitution 

 and discharge, of every kind of living substance, that physiologists by com- 

 mon consent use the term Stimulus (Heiz), meaning thereby nothing more than 

 that it is by external disturbing or interfering influence of some kind that 

 energies stored in living material are (for the most part suddenly) discharged. 

 Now, if I were to maintain that restitution is not autonomic, but determined, as 

 waking is, by an external stimulus — that it differed from waking only in the 

 direction in which the stimulation acts, i.e. in the tendency towards construction 

 on the one hand, towards destruction on the other, I should fairly and as clearly 

 as possible express the doctrine which, as I have said, the two distinguished 

 teachers I have mentioned, viz., Dr. Gaskell and Professor Hering,' have embodied 

 in words which have now become familiar to every student. The words in question, 

 ' anabolism,' which being interpreted means winding up, and ' catabolism," running 

 down, are the creation of Dr. Gaskell. Professor Bering's equivalents for these are 

 ' assimilation,' which, of course, means storage of oxygen and oxidisable materia), 

 and ' disassiniilation,' discharge of these in the altered form of carbon dioxide and 

 water. But the point of the theory which attaches to them lies in this, that that 

 wonderful power which living material enjoys of continually building itself up out 

 of its environment, is, as I have already suggested, not autonomic, but just as 

 dependent on occasional and external influences, or stimuli, as we know the dis- 

 integrating processes to be ; and accordingly Hering finds it necessary to include 

 under the term stimuli not only those which determine action, but to create a new 

 class of stimuli which he calls Assimilations-Iteize, those which, instead of waking 

 living mechanism to action, provoke it to rest. 



It is unfortunately impossible within the compass of an address like the present 

 to place before you the wide range of experimental facts which have led two of 

 the strongest intellects of our time to adopt a theory which, when looked at 

 h priori, seems so contradictory. I must content myself with mentioning tbat 

 Hering was led to it chiefly by the study of one of the examples to which I referred 

 in my introduction, namely, the colour-discriminating function of the retina. Dr. 

 Gaskell by the study of that very instructive class of phenomena which reveal to 

 us that among the channels by which the brain maintains its sovereign power as 

 supreme regulator of all the complicated processes which go on in the diflerent 

 parts of the animal organism, there are some which convey onlj- commands to 

 action, others commands to rest, the former being called by Gaskell catabolic, the 

 latter anabolic. To go further than this would not only wear out your patience but 



' Hering, Zur Thcorie tier Vorgiingr in der lehendigen Suhsian:, Trajjue, 1888, 

 pp. 1-22. See also a paper by Dr. Gaskell iu Ludwig's Festschrift, Leif sic, 1S8S, p. 116. 



