xl SEVENTH REPORT—1837. 
Under the head of Theories of Elastic Fluids, the author has intro- 
duced some valuable remarks upon the memoirs of Poisson, on the 
equilibrium and motion of elastic bodies, on the equilibrium of fluids, 
and the pressure of fiuids in motion; and also on Laplace’s theory of 
Capillary Attraction; for which I must refer to the Report. 
We have next two reports on the Comparative Botany of Scotland 
and Ireland, by Mr. Mackay and Professor Graham, of Edinburgh. 
The first indicates the more remarkable plants that characterize the 
neighbourhood of Dublin and Edinburgh. In the second, Mr. Mackay 
points out the effect of climate on the Flora of Ireland. Ireland, it is 
true, has fewer species of plants than Great Britain, and possesses fewer 
alpine plants than Scotland. Its position and moister climate, how- 
ever, put it in possession of many plants not found in Great Britain, 
but of species occurring in Spain and Portugal, among which may be 
noticed Erica Mediterranea, Erica Mackiana, Pinguicola grandiflora, 
Arbutus unedo, Menziesia polyfolia. 
The Reports from the London and Dublin sub-committees on the 
Motions and Sounds of the Heart, in this and the last volume, will 
interest the physiologist and the physician. Ever since the application 
of the stethoscope, by Laennec, to the investigation of pectoral diseases, 
the sounds of the heart have been anxiously explored—its normal 
sounds studied, and its abnormal bruits eagerly inquired into, as im- 
portant diagnostics of health and disease. The causes of those sounds 
have been matter of dispute ; the investigation was recommended by 
the Association; and a sum appropriated for the expense of experi- 
ments on the subject. The Reports are the results of the labours of 
two sub-committees,who agree on the principal points,viz., that the first 
sound is produced during the systole, or contraction of the ventricles : 
and that the second sound is produced by the sudden check which the 
action of the semilunar valves gives to the current of blood impelled 
against them, by the elasticity of the arteries. In the second Dublin 
Reports, the abnormal sounds are illustrated by some ingeniously-de- 
vised experiments: but both sub-committees admit, that the motions 
and sounds of the heart require further investigations. 
The Dublin Committee on the Pathology of the Brain and Nerves 
express their opinion, that to arrive at any accurate conclusions on so 
extensive and difficult a subject, a very large number of cases must be 
first submitted to examination, their symptoms during life accurately 
noted, and minute examinations instituted after death. One hundred 
and seventy-cight males and two hundred and ninety-four females, 
labouring under nervous affections, are in the Dublin House of In- 
a aa 
