of Edinburgh, Session 186-1-65. 387 
of theology, and which in all of these sciences is equally important. 
It represents the external world and its Creator as possessed of one 
immaterial and spiritual essence — poiuer and intelligence being the 
attributes of the Creator, and power subordinate and sustained the 
characteristic of the creation. 
The objection to a system of pure dynamics will probably be this. 
It will be said forces cannot exist except as properties of matter. 
The belief in the necessity of matter is all but universal. This 
arises, we think, from a law of the mind, which when it reflects on 
any thing as existing immediately, and of necessity, assigns a cause 
for its existence. The generality are satisfied to regard the pro- 
perties perceived as constituting the thing or object. The object is 
thus a hard or soft, a black or white, or coloured thing. The man 
of science applies his mind to the consideration of the properties, 
and afterwards to the consideration of the thing itself, as if they were 
different entities, and he thus assigns matter as the cause of the 
properties he observes. The author also believes in a cause for the 
forces of which he has spoken ; but as he has not matter to fall 
back on, he is compelled to assign as the cause that Being who is 
the centre of all pow^r and wisdom, and Avho manifests these 
attributes to his creatures in the vast and complex arrangements of 
a dynamical universe. 
The tendency of speculative philosophy has been to run into 
idealism. This has been its fate in G-erman^q and it is to be 
feared it may come to the same conclusion in Scotland. The 
author would deeply deplore such an end to our boasted Scottish 
philosophy. The ultimate foundation of all reality has been ad- 
mitted by nearly every philosopher to be the Supreme Being. If, 
then, the theory propounded should assist abler hands in establish- 
ing realism directly on this foundation, the author would feel in no 
ordinary degree gratified and rewarded. 
2. On the Nudihranchiate Mollusca of St Andrews ; Ed- 
wardsia ; and the Polyps of Alcyonium digitatum. By 
W. C. MTntosh, M.D., F.L.S. Communicated by Pro- 
fessor Allman. (Accompanied by various Drawings.) 
The ISTudibranchs owe their prominence in British zoology to the 
