454 THIRD REPORT — 1833. 



together with the internal surfaces, we shall find that the su- 

 perficies of the human brain is greater in relation to its bulk 

 than that of any other animal. In addition to the surfaces 

 already known, Dr. Macartney has ascertained the existence 

 of ventricles (so called) in the bulb of the olfactory nerves, and 

 in the optic thalami of the human adult brain. In the thalami 

 the distinction of surface is obscure, but in the olfactory tu- 

 bercles it is sufficiently plain. 



The author concludes with stating his belief that every as- 

 semblage of the nervous filaments in the form of plexus is 

 destined to fulfill an especial purpose, and with the anticipation 

 that at no distant period we shall be able to understand many 

 of the phsenomena of sensation which have been hitherto 

 veiled in the utmost obscurity. 



Abstract of Observations on the Motiotis and Sounds of the 

 Heart. By Hugh Carlile, A.B., Demonstrator in the 

 School of Anatomy in the University of Dublin. 



The circumstances in the history of the heart's action which 

 have been most the subject of controversy within late years 

 may be enumerated as follow: — 1st, the expansion and con- 

 traction of the auricles and ventricles, commonly called their 

 'systole' and 'diastole'; 2nd, the beat of the heart against 

 the side of the chest ; 3rd, the arterial pulse ; and 4th, the 

 sounds perceptible during the heart's motion. With a view to 

 the explanation of these phaenomena the author has made some 

 experiments on living animals, the results of which he was 

 desirous of communicating to the Association. 



In experiments of this kind it is desirable, as well for ensuring 

 the means of accurate observation as for the sake of humanity, 

 to diminish as much as possible the suffering of the animal. 

 This can be accomplished by the use of the artificial respiratory 

 apparatus, the animal having been suddenly deprived of sensa- 

 tion without shedding its blood. But the author has found 

 that the application of this apparatus causes the heart to con- 

 tinue and terminate its motions in an unusual manner, and is 

 therefore liable on some points to mislead the observer. In 

 those cases in which the employment of artificial respiration is 

 not expedient, there is much advantage in using very young 

 animals for experiment. In this stage of life, as well as in ani- 

 mals of the inferior classes, the different organs appear to have 

 a comparatively independent existence ; and as their functions 

 are in many instances performed with little disturbance under 



