Page:Philosophical Transactions - Volume 004.djvu/149

 ing in them the Spirits, others making them the receptacles of the Excrements of the Brain,—and both perplext 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 shewed the imperfection in the common ways, he proposes and recommends that (though difficult one) of continuing the filaments or threds 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 examins particularly the Systemes of Dr. Willis and Monsieur Des-Cartes. In the former special notice, that the Author there of lodges the Common Sense in the corpus Striatum; the Imagination in the Corpus Callosum; and the Memory in the Grayish 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 mere two sorts of Streaks or Rays, some ascending, some descending, he finds, that a separation being made of the Gray body from the White, those Rays will be found to be all of the same nature, that is, they make part of the White substance of the Corpus Callosum which passes towards the Marrow of the Back, separated in divers Layers by the intervening of the Grayish Substance. Which being so, saith he, with what certainty can we be made to believe, that those three Operations are performed in those three Bodies? And who can tell us, whether the nervous Fibres have their beginning in the Streaked Body, or whether they rather pass through the Callous Body into the Gray Substance?

In the latter of M. Des Cartes, he finds, that that Philosopher hath rather devised, in his Treatise of Man, such an Engine, that performs all the actions, Men are capable of, than described Man, as really he is; which he undertaketh to prove by divers instances, taken from the Cartesian fabrick of the parts of the Brain: in the doing of which our Author showes great dexterity, skill, and accuratenes. And from hence he proceeds,