VOL. IV.] PHILOSOPHICAL TRANSACTIONS. 387 



is full of those old sciarri which former eruptions have cast forth, though the 

 people remember none so large as this last, or that burst out so low. This 

 country is notwithstanding well cultivated and inhabited ; for length of time has 

 either mollified much of those old sciarri, or new mould or ashes have over- 

 grown them ; though there still remains much country, which probably will 

 never be made serviceable. 



All Account of M. Stenos Discours sur l' Anatomic du Cerveau. 

 Paris, 1669, l'2mo. N" 51, p. 1034. 



In the beginning of this discourse the author represents, that those who 

 search after solid knowledge, will find nothing satisfactory in all that has been 

 hitherto written concerning the brain ; that all, which anatomists agree in, is 

 only, that it consists of two substances, a white and a greyish, and that the 

 former is continued with the nerves that are distributed through the whole 

 body ; and the latter serves in some places for a kind of cortex to the white, and 

 in others severs the white filaments from one another. But that they are yet 

 ignorant what those substances are, in what manner the nerves are joined in the 

 white, and how far their extremities advance in it; from which disposition yet 

 depends all the diversity and variety of our sensations and motions. And as for 

 the ventricles or cavities of the brain, he affirms them to be no less unknown 

 than its substances; some anatomists lodging in them the spirits, others mak- 

 ing them the receptacles of the excrements of the brain ; and both perplexed 

 in assigning the source and issue of the excrements and the spirits, and the 

 manner of the production of the latter. 



Besides this, he finds a great defect in the way of dissecting the brain, and 

 having shown the imperfection in the common ways, he proposes and recom- 

 mends that, though difficult one, of continuing the filaments or threads of the 

 nerves through the substance of the brain, to see where they pass, and where 

 they terminate. 



Next, he entertains the reader with an enumeration of the chief errors of 

 anatomists touching the brain. And here he examines particularly the systems 

 of Dr. Willis and Monsieur Descartes. In the former he takes special notice, 

 that the author thereof lodges the common sense in the corpus striatum ; the 

 imagination in the corpus callosum, and the memory in the greyish substance 

 which encompasses the white. But then he declares, that these assertions are 

 very obnoxious; for, whereas Dr. Willis describes that corpus striatum, as if 

 there were two sorts of streaks or rays, some ascending some descending, he 

 finds, that a separation being made of the grey body from the white, those rays 



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