338 



RESPIRATION. 



functions of the numbers expressing the corresponding per-centage 

 of carbonic acid. Thus for every expiration, without reference to 

 duration, there is a constant amount of carbonic acid (of 2 '5-8), to 

 which we must add a second value expressing the quantity of car- 

 bonic acid exactly proportional to the duration of the respira- 

 tion. We subjoin the following table in elucidation of this 

 proposition : 



[The author here quotes Vierordt's formula, representing (as 

 that chemist believes) the connexion between the per-centage of 

 the carbonic acid and the number of respirations in a minute. As, 

 however, it would not be intelligible to the general reader without 

 a much fuller explanation than is given in the original text, we 

 deem it advisable to omit it. G. E. D.] 



Sturmer,* who carried on a series of investigations on this sub- 

 ject under the direction of Marchand, obtained somewhat different 

 results from those of Vierordt, although upon the whole they 

 arrived at tolerably similar conclusions. As Sturmer and Mar- 

 chand's results did not, however, admit of being expressed by 

 Vierordt's formula, they attempted in some degree to modify it. 

 Several objections were advanced against Vierordt's method, as, 

 for instance, the expiration into the expirator with open nostrils, 

 the employment of a solution of common salt as a separating 

 fluid, and the neglect of the difference of the tension of its vapour 

 from that of pure water, the inaccurate determination of the tem- 

 perature of the air in the anthracometer, and the uncertainty in the 

 reading of the water-line, &c. Most of these objections were, 

 however, recognised and specified by Vierordt himself, and we 

 agree with him in thinking that they do not materially influence 

 the main results ; for although we by no means hold the view that 

 a very large number of less exact experiments are able to give a 

 better result than a few very accurate observations, (since, if this 

 were the case, an astronomer might as well content himself with 



* Observ. de acidi carbonic! respiratione exhalati quantitate. Halis, 1848. 



