YOL. XVJl.] PHILOSOPHICAL TRANSACTIONS. 403 



gums; the other truly bone, consisting of laminae or plates, as the other 

 bones do. 



In thie second discourse is given an account of the manner of accretion and 

 nutrition in general, and then particularly in the bones. The matter which 

 gives an increase to the animal is originally from the chyle, the particles of 

 which designed for nourishment being elaborated in the mass of blood, and so 

 reduced nearer to the nature of a succus nutritius, and disposed for a separation, 

 are secerned from the sanguineous mass, by glands seated on the sides of the 

 arteries all over the body. And here the author takes occasion to speak of 

 glandular secretion. 



He then goes on with the affair of accretion, and the account is in short 

 this, that the nutritious particles, being separated by the glandules placed in 

 the sides of the arteries, are carried into those small nervous pipes, or inter- 

 stices of the fibres where the spirits move, so that they fall in the way of the 

 spirits motion. 



Nutrition he makes to be no reparation of the loss of the substance of the 

 solid parts ordinarily, but only a continual succession and supply of spirits, 

 and of all those fluid parts, which fill the containing parts, and preserve them 

 distended. 



The third discourse concerns the marrow, which has blood vessels, both veins 

 and arteries. The organs by which the medullary oil is separated, are small 

 vesicles or glandules, which are conglomerated into distinct lobules, contained 

 in several membranes or bags, which lie in one common membrane, investing 

 the whole marrow : all which vesicles, bags and membrane are propagated from 

 the exterior coat of the arteries. The passage of the medullary oil from all 

 parts of the marrow to the bone is not by ducts, but by pores formed in the 

 vesicles, by which it passes from one to another, till it arrives at the sides or 

 extreme parts of the bone. The medullary oil, which is supplied to the inter- 

 stices of the joints, passes into them by passages penetrating through the bone 

 into these cavities, and formed for this end. The use of the medullary oil, is 

 either common to all the bones, or more proper to the joints. It is necessary 

 to preserve the temper of the bones, and prevent them from being brittle. 

 In the articulations, 1. It lubricates the extremities of the bones, and so makes 

 them more easy to be moved. 2. It preserves the ends of the articulated bones 

 from an inordinate incalescence. 3. It prevents the attrition of those parts of 

 the bones, which are rubbed one against another. It is likewise beneficial 

 to the ligaments of the joints in preserving them from dryness and rigidity, 

 and lubricating those parts of them, which slide upon the bone. Those carti- 

 lages also which are joined to any of the bones it preserves flexible. 



