VOL. XXVII.] PHILOSOPHICAL TRANSACTIONS. Gig 



appear in clusters, and are seldom scattered here and there. Their figure is 

 roundish, and in size they equal a silk-worm's egg, if inspected as soon as the 

 body is opened; but if the meninx be macerated in vinegar for a month, or 

 more, they are larger than a millet seed. In old people, and in those who have 

 died of a lingering disease, they may be seen by the naked eye, without any 

 microscope, or previous preparation. They are incompassed with fine carneous 

 fibres: whence they put on a pale colour; but when these fibres are much relaxed, 

 as happens in an hydrocephalus, or comatose distempers of the brain, they be- 

 come white and very large. 



From the aforesaid glands innumerable fine threads arise, which are only their 

 excretory vessels, and are spread all over the inside of the pia mater, being 

 accompanied and strengthened in their course by fibres and other blood vessels. 

 It is these fibres which join the meninges to one another : and if you take care 

 that the dura mater be not hurt in taking off the upper part of the skull, in di- 

 viding these membranes, you may observe liquors of different colours ooze and 

 drop from them when cut. Our author is not positive that these excretory ducts 

 penetrate into the medullary substance of the brain ; but affirms, that they 

 creep along its inner protuberances and accidental cavities. This discovery con- 

 firms what Bohn and some others have said about the lymphatics of the brain ; 

 but before our industrious author, none ever so much as pretended to fix their 

 origination, which he has traced from the glands lodged in the longitudinal sinus, 

 as above. The use he assigns to these glands, is to separate and strain a par- 

 ticular kind of humour from the blood ; which, in his opinion, may serve to 

 keep the membranes and surfaces of the cavities and protuberances of the 

 brain from growing too dry by their continued motion. 



De Mensura Sortis, seu, de Probahilitate Eventuum in Ludis a Casu Fortuito 

 Pendentihus. j^utore Ahr. De Moivre, R,S.S. N° 329, p. 213. 



This long paper, on the doctrine of chances, it is unnecessary here to repeat ; 

 because its contents were only given as a specimen of this art, which the author, 

 7 years after, enlarged and perfected into his celebrated treatise, first published 

 in 1718 ; where the whole may be seen to much more advantage. This speci- 

 men also gave rise to several disputes on the subject, with the continental ma- 

 thematicians ; some account of which may be seen in the author's treatise just 

 mentioned ; and still more fully in his Miscellanea Analytica, published in 

 1730. 



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