Ik: I 'i. iü
" iik!!j , i.
h I
16 O B S E R V A T I O N S ON THE
found to have nearly the fize and ihape of a fimilar cafe, iketched from memory,
in Tab. III. Fig. 4.
C H A P .
• In 1764, December 13. 1 read to the Philofophical Society of Edinburgh, * a paper on the com-
' munication of the ventricles of the brain with each other, and on their fuppofed communication with
' the medulla fpiualis, -with fome remarks on the hydrocephalus and fpina bifida, and on tapping in
' thefe difeafes, illuftrated with figures.'
This was referred to Dr Whyti, in order that he might report concerning it to the Society.
In this paper all the above circunillances were mentioned, and, for upwards of eleven years before
that time, to wit, from the 1753, ^ demonilrated the communications I have defcribed in the Anatomical
Theatre.
By an accident, I have in my pofleflion a note taken by Dr Morgan, no"w phyfician and profeflbr of
phyftc in Philadelphia, from my leéture on this fabjed in 1762. The Doftor, who was then a ftudenc
in this place, wrote an account of what he had feen, in that and the preceding year, to Sir John Pringle
at London ; and, leil he ihould have mifunderftood what I had delivered, fent me a fcroU of the letter
he intended to fend to Sir John. He chofe to write in Latin as an exercife in that language.
Ed'm. Dcc. 28. 1762. Hanc epiftolam tibi mittere diftuli, poftquam earn hue ufque fcripferam, ut
alia fruar occafione videndi \'entriculorum commercium fuperiorum in fchola hac anatómica, a noftro
ProfelTore Monro filio, demonftratum: Et quoniam hoc dare et perfpicue fañum eft, defcriptionem
ejus nunc fubjiciam, ipfiflimis quibus ille fententiis, quoufque poffum, utens.
Inquit, ' Anni decern nunc elapfi funt a quo communicationem mutuam inter ventrículos cerebri la-
' tendesobfervavijetmethbdofequenteillam defcribere folitus fum, quam, praetermiffis cerebrorum
' fanorum fedionibus, in quinqué hydrocephalo mortuis etiam vidi.
' lufni corporis partem anteriorem fornicis, i t flexum quem plexus cho-
' roideus, tranfcundo a tertii venrriculi fummo in ventrículos laterales, fàcit, foramen eft natura effor-
' matum, quod in hydrocephalo ita auftum vidi ut digiti apicem caperet. Dum per hanc viam ven-
' triculi laterales cum fe invicem communicant, manifeftum eft cos, fubter foramen illud, identidem
' quoque cum tertio ventrículo communicare,' See.
N E R V O U S SYSTEM. 17
C H A P T E R V.
Of the Abforbent Veflels of the Encephalon, and of the
Infuiidibuhim and Glandula Pituitaria.
S E C T . I.
L T H O U G H no late and accurate author has pretended to defcribe
valvular lymphatic abforbent veflels in the brain of man or quadrupeds,
yet there is no juft: ground for doubting of their exillence.
1. In the jirjl place, it does not appear that any perfon has attempted,
by proper experiments, to difcover them in living quadrupeds; and, although
they had, as their trunks muft be fituated at the under part of the
brain, they could not well have been brought into view.
After death, it is fo very diflacult to find the lymphatics in many of our
organs, that the argument of their not exifting, becaufethey have not been
defcribcd, will have moil weight with thofe who are leaft verfant in fuch
rcfcarches.
2. As the lymphatic veflds are known to enter into the texture of almoil
all our other organs ; and as, by attending to difeafes, I have feen evidence
that they exift in the eye, and within the cavities of the bones and
joints, where no author pretends to have traccd them with the knife, it
would farely require fome more powerful argument than any which has
hitherto been employed, to pcrfuade us, that, within the head, abforption
is performed in a way quite different from what takes place in the reft of
the bodv.
E . In