O MUSCULAR WORK 
taking the pulse-rate of the subject. At the present day, when the relation- 
ship between the pulse-rate and metabolism is continually being emphasized, 
it is interesting to note that 130 years ago the importance of this relationship 
was also recognized by Lavoisier. In the experiments on muscular work a 
pedal arrangement, which is shown beneath one of the tables and to which 
the right foot of the subject is attached, was evidently used for performing the 
work. The amount of work was probably computed from the movements of 
the pedal. Of further significance is the fact that Lavoisier and Seguin recog- 
nized in their experiments that the subjects should be without food in the 
morning, a prerequisite of all modern respiration experiments. We can do 
no better than sum up the results in their own words: 
II resulte des experiences auxquelles M. S6guin s'est soumis, qu'un homme a jeun, dans 
un 6tat de repos et dans une temperature de 26° de thermometre de rnercure, divis6 en 80 
parties, consomme par heure 1210 pouces cubes (24.002 litres •) d'air vital; que cette con- 
sommation augmente par le froid, et que le meme homme, egalement a ieun et en repos, mais 
dans une temperature de 12° seulement, consomme par heure 1344 pouces (26.660 litres) 
d'air vital. 
Pendant la digestion, cette consommation s'eleve' a 1800 ou 1900 pouces (37.689 litres). 
Le mouvement et l'exercice augmentent considerablement toutes ces proportions. 
M. Seguin 6tant a jeun et ayant 61eve pendant un quart d'heure un poids de 15 livres 
(7.343 kilograms ) a une hauteur de 613 pieds (199.776 metres ), sa consommation d'air 
pendant ce temps a 6t6 de 800 pouces, c'est-a-dire de 3200 pouces (63.477 litres) par heure. 
Enfin, le meme exercice fait pendant la digestion a porte a 4600 pouces (91.248 litres) 
par heure la quantity d'air vital consomme. Les efforts que M. Seguin avoit faits dans cet 
intervalle oquival^ient a l'elevation d'un poids de 15 livres (7.343 kilograms) a une hauteur 
de 650 pieds (211.146 metres) pendant un quart d'heure. 
As a definitely planned series of experiments to study the influence of 
muscular work on the gaseous metabolism, this investigation is without prece- 
dent. That the results obtained are not in accord with those obtained by 
the use of the modern experimental technique can not dim in any way the 
brilliancy of the conception of the research. 
Aside from these researches of Lavoisier and Seguin, the experi- 
mental evidence secured by the earlier investigators dealt almost exclusively 
with the gaseous excretion while the subject was at rest, the influence 
of muscular work being investigated but rarely. Owing to a limited tech- 
nique, the determinations were as a rule confined to the percentages of 
carbon dioxide in the expired air. As an example of the wide variations 
found in the percentage of carbon dioxide in air expired in a supposedly 
normal manner, we may cite a collection of analyses gathered by Valentin. 6 
(See Table 1.) 
Of the few researches regarding the influence of muscular work on the 
gaseous metabolism which followed those of Lavoisier and Seguin, that of 
Prout is the earliest. Prout, c who used the method then in vogue of deter- 
mining only the percentage of carbon dioxide in the expired air, states that 
he found the effects of exercise varied according to the nature and degree of 
the exercise and also according to its time and duration. Moderate exercise, 
as walking, seemed always at first to increase the percentage of carbon dioxide 
in the expired air, but after having been continued for some time, it ceased 
° The reduction of pouces to litera, and of pounds and feet to kilograms and meters respectively, has been.made 
by Gavarret (Physique m6dicale, Paris, 1855, p. 330). 
& Valentin, Lehrbuch der Physiologic des Menschen, Braunschweig, 1847-51. 
c Prout, Annals of Philosophy, 1813, 2, p. 328. 
