105 



March 8, 1832. 



WILLIAM GEORGE MATON, M.D., Vice-President, 

 in the Chair. 



The reading of Dr. Marshall Hall's paper, entitled, " On the In- 

 verse Ratio which subsists between Respiration and Irritability in the 

 Animal Kingdom; and on Hybernation," was concluded. 



The object of the author, in the investigation which he has un- 

 dertaken, and of which some of the results are given in the present 

 paper, is to establish a law of the animal economy, which he ex- 

 presses in the following terms : " The quantity of the respiration is 

 inversely as the degree of the irritability." Other authors, such as 

 Cuvier, attaching a different meaning to the term irritability, have 

 stated this property, in the different classes of animals, as being di- 

 rectly proportional to the energy of the respiratory functions; the 

 purposes of which they have considered to be those of restoring to 

 the exhausted muscular fibre its contractile power. The author of 

 the present paper regards animal life as consisting in two essential 

 ingredients; namely, stimulus and irritability; atmospheric air being 

 the principal source of the former ; the heart, where it exists, being 

 the principal organ of the latter ; and the blood being the medium 

 by which these are brought into contact. 



For the purpose of ascertaining the quantity of respiration in any 

 given animal, the author contrived an apparatus, to which he gives 

 the name of the i Pneumatometer . It consists of a glass jar inverted 

 over mercury, and over the mouth of a bent tube, by which it com- 

 municates with a water-gauge of one tenth the capacity of the jar. 

 Annexed to this apparatus, but unconnected with it, is a glass ball, 

 containing ten cubic inches, and terminating in a tube, bent at its 

 upper part, and of the capacity of one cubic inch, and inserted into 

 a wider tube containing water, so as to correspond in all its pneu- 

 matic conditions with the jar and its gauge, and to point out what- 

 ever changes may have taken place in the volume of the air examined 

 in the course of the experiment, from circumstances extraneous to it, 

 such as variations of temperature, or of barometrical pressure. The 

 animal, whose respiration is to be examined, is placed on a stand and 

 covered with a jar : and the carbonic acid produced is absorbed by 

 pieces of calico moistened with a strong solution of caustic potass, 

 fixed by a wire frame in the upper part of the jar. The animal, at 

 the end of the experiment, is withdrawn under mercury, without 

 displacing the jar ; the space it had occupied is filled with an equal 

 volume of atmospheric air admitted into the jar; and the volume of 

 oxygen gas absorbed is estimated by the column of water which 

 has risen in the gauge. 



From the facts detailed by Harvey, Goodwyn and others, which 

 establish that in asphyxia the left ventricle of the heart ceases to 

 contract before the right ventricle, the author infers that the irrita- 

 bility of the latter is greater than that of the former • and proposes 

 to distinguish the first as arterio -contractile, and the latter as ve.no- 



