VOL. XXXI.J PHILOSOPHICAL TRANSACTIONS, 487 



of which I placed before a miscroscope, and caused it to be delineated. This 

 piece is represented by abkc, fig. 7, having been cut ofF transversely, and as 

 thin as possible, from the rib, with part of the periosteum, as from k to c, 

 still adhering to it, and another part of it torn off from the bone, as noted by 

 BKD, only that in some places the bone and membrane are still united by vessels 

 torn out of their places, that run from one to the other. In this figure defc 

 represents the periosteum, and the part eghif is something lying upon it, which 

 I could not tell what to make of, though it appeared to be membranous. 



I had likewise some very thin slices shaven off from the rib both of an ox, 

 and of a calf, from which I tore off the periosteum entirely, or at least as much 

 as possible ; after which I caused the edge of the bone it had stuck to, to be 

 represented by the crooked line, lmn, fig. 8. 



In %. 9, opa represents the edge of another small slice of bone, from which 

 the periosteum has been torn off; by which appearance it should seem, that the 

 union of the periosteum with the bone is so firm and strong, that in separating 

 it, some of the superficial particles of the bone are torn off with it. I have 

 likewise discovered some vessels running along within the marrow-bone of the 

 shank of an ox, that seemed to be blood-vessels. 



Since now it appears from our observations, which have been made with 

 great diligence and care upon bones of all kinds, that the bones do for the most 

 part consist of exceedingly small vessels, which vessels arise from the inner 

 hollow, or spongy part of the bone, and passing through the superficial or cor- 

 tical substance, enter the periosteum, and are from thence continued, even 

 into the utmost parts of the body ; we may from hence reasonably conclude, 

 that in a healthful body, as there is a constant supply of an oily substance con- 

 veyed into the bones, so this is again constantly carried out from the bones by 

 means of these vessels, into all parts of the body, even to the extremities of 

 the fingers. As an evident proof of this, let any one lay the ends of his fingers 

 on a clean and bright pewter plate, and he shall find the pewter appear soiled in 

 the place where he has touched it ; for in reality this soil is nothing else, but 

 some oleaginous particles discharged from the ends of his fingers. There is 

 indeed something of a watery substance mixed with the oily particles, but this 

 soon evaporates, and leaves the oily particles on the plate. 



Of a prceternatural Tumor on the Loins of an Infant^ attended with a Cloven 

 Spine, By Dr. Rutty, F. R. S. N« 366, p. 98. 



Mr. Ruysch, in an observation on the spina bifida, takes notice that other 

 writers have described it to be cloven into 2 equal parts lengthwise ; whereas 



