VOL. II.] PHILOSOPHICAL TRANSACTIONS. 215 



eases to wliich these parts are liable is esteemed very difficult and intricate, and 

 particularly the true causes of convulsions are of a very deep research. With 

 a view to the elucidation thereof, this author reasons after this manner : He 

 teaches that there are indeed animal spirits, that they constitute the being of the 

 corporeal soul, and are also the next and immediate instruments of all animal 

 motions, producing them by a kind of explosion or shooting; upon which elas- 

 tic or explosive power he establishes his whole doctrine of convulsions. To 

 which he annexes a disquisition on the scurvy, as relating to the same doctrine, 

 and grounded upon the same hypothesis. 



Comparison between burning Coal and shining Wood. By Mr. Boyle, 



iV" 32, p. 605. 



Their resemblances are as follow. — 1. Both live coals and shining wood are 

 luminous by their own light ; for both of them shine the more vividly, by how 

 much the place wherein they are put is made the darker by the careful exclu- 

 sion of the adventitious light — 2. Both shining wood and burning coal require 

 the presence of the air, and that too of a particular density. — 3. Both shining 

 wood and a burning coal having been deprived for a time of their light, by the 

 withdrawing of the contiguous air, may presently recover it by letting in fresh 

 air upon them. — 4. Both live coal and shining wood are easily extinguished by 

 water and many other liquors. This is evident as to the coal. And on wetting 

 a piece of shining wood with a little common water in a clear glass, it presently 

 lost all its light. The event was the same with strong spirit of salt, and also 

 with weak spirit of sal ammoniac ; as also with highly rectified spirit of wine, 

 and with rectified oil of turpentine. — 5. As a live coal is not extinguished by 

 the coldness of the air, so neither is a piece of shining wood. 



Their differences are as follow. — 1. The first difference observed between a 



his treatises de Fermentatione^ de Febribus, de Urinis, de Cerebri Anatome. In the last-mentioned 

 treatise, which was his cfief-d'oi/vre, he had the assistance of Lower in tlie anatomical dissections, 

 as well as in the Latin composition, and of Sir Christopher Wren, (at tliat time Savillian professor of 

 astronomy in the university of Oxford,) in the drawings for tlie plates. These publications were fol- 

 lowed by tliework above noticed (Pathologia Cerebri), by his Anima Brutorum, and lastly by his 

 Pharmaceutice Rationalis; all of which have been printed togetlier at different times under the title of 

 Opera Omnia, in fol. and in 4to, He died in 1675. Dr. Willis was too much addicted to chemical 

 theories, on which he endeavoured to establish a pathology incompatible widi the properties of living 

 bodies. Nevertheless much ingenuity is displayed in all his writings, and those which relate to anato- 

 mical subjects may be consulted with advantage for the descriptions and accompanying plates. Suc- 

 ceeding anatomists, however, have remarked that he has not always distinguished betw'een the parts as 

 they appear in the human and brute subject; having at times made dissections of the latter subser\ient 

 to exemplifying and illustrating tlie structure of the former. 



