TRANSACTIONS OF SEOTION I. 745 
which are associated with these three forms of activity. If analogies are to be 
sought for, it is here they will be found. 
I submit to the Section, and particularly’ to those members of it who are 
engaged in experimental researches on the subject, that the most important con- 
trast between the concomitant chemical processes of gland function and muscle 
function consists in this, that whereas the former is not in any marked degree 
catabolic, the dominant process in the oxidation which is inseparably associated 
with the performance of muscular function zs catabolic. We can readily account 
for this by reference to the fact that whereas the processes in muscle and in 
reflex centre are excitatory, those in glands are for the most part determined by 
stimuli of a very different kind from those that evoke nervous or muscular 
action, which last act exclusively as liberators of catabolic processes which are 
waiting to be discharged. 
We have long been accustomed to regard the process by which, in muscle, 
chemical is translated into mechanical energy as explosive and instantaneous, 
and to take the end result—the discharge of carbon dioxide—as the necessary 
concomitant of the production of heat and work; but, as I remarked before, 
Dr. Fletcher recently published experiments which seem to show that for the 
attainment of this ultimate result it is essential that the muscle should be 
abundantly supplied with oxygen, in failure of which the oxidation process may 
stop short before its completion. I trust that we shall have the advantage of 
hearing to-day the further results of his researches, and particularly that he will 
give us information as to the relation between efficiency of contraction and the 
degree of completeness of the oxidation process. 
In conclusion, the questions which present themselves are :— 
(1) Whether it may be generally stated that the oxygen which is conveyed 
to the living matter of the tissues by the blood zs stored as ‘intramolecular 
oxygen’ until it ts required for the performance of catabolic functions, and, if so, 
what is the chemical relation between the stored oxygen and the living molecules 
by which it is held? In submitting this question I must again ask that the use 
of the term ‘living molecule’ may be condoned. 
(2) Whether it may be assumed that every disintegrative process con- 
ditionates a subsequent integrative process, by which the status quo is restored in 
the same living molecule ; if so, does the anabolic effect which in muscle follows 
the change of form constitute as much a part of the response to stimulation as 
the catabolic etfect which precedes the change of form? Can this be said of the 
chemical process which is associated with functional activity in gland? 
Dr. W. M. Fletcher pointed out that in the muscle cell only the catabolic 
processes had been effectively studied, and that these are characteristic of the 
special material giving energy for contraction—a material probably without 
analogue in the gland cell. The classical conceptions, due to Pfliiger and to 
Hermann, of this material as a highly oxygenated substance breaking down, 
whether rapidly as in contraction, or slowly as in survival periods, by inevitable 
stages to the ultimate stages of carbonic acid and water, irrespective of a contem- 
porary supply of oxygen, were discussed and compared with the views of Verworn. 
It was urged that while a preliminary oxygenation of the living molecule may be 
admitted on wide grounds as the condition of irritability, such a conception by no 
means precludes the idea of additional oxidative processes occurring at some stage 
or stages of the catabolic disintegration. Disintegration effected under anaérobic 
conditions might, on this view, stop short of its normal end products, these being 
replaced by representatives of earlier stages in the breakdown. Evidence in this 
direction has been got from three main classes of experiment. In the case of 
excised muscle, Dr. Fletcher’s observations of the relation of oxygen supply to 
the yield of carbonic acid in rest and in activity, and to the onset of fatigue and 
of rigor, were described, and held to be incompatible with the view that the 
entrance of oxygen conditioned the lability of the molecule without further 
influence upon the subsequent course of catabolism. A second class of evidence 
was derived from the work of Chauveau and Kauffman, Ludwig and his pupils, 
Minot and others, upon the respiration of muscles with artificial circulation, An 
