VOL. XVII.J ,'/■. PHILOSOPHICAL TRANSACTIONS. tftfil 



ruined, and for the most part with a dreadful slaughter of ihe people. The 

 southern coasts, as Licati, Terra Nova, and Gircuti, have suffered damage in 

 their buildings. And all the castles of the valley of Einone near Mongibello 

 are cracked and broken, or thrown down. 



Extract of a Letter from Mr. Anth. f^an Leuwenhoeck, containing several 



Observations on the Texture of the Bones of Animals compared with that of 



Wood ; also on the Bark of Trees : on the little Scales found on the Cuticula, 



&c. N° 202, p. 838. 



Some years since I conceived the bone to be constituted of globules ; but 

 finding my mistake, I retracted that opinion ; for what I then took for globules 

 was the tops of the tubes or cylinders, of which the bone is composed. Conti- 

 nuing my endeavours, at length I found plainly, in the thigh bone of an ox, 

 that it consisted of four sorts or sizes of tubes, some of which are so very small 

 and close united, as not easily to be discerned in a bone cut smoothly across, 

 nothing but globules appearing ; but when it is broken, some shivers are sepa- 

 rated, in which these tubuli may be seen. 



Another sort of these tubuli, some of which are 6 times larger than the 

 former, are yet hard to be discovered ; for though the knife be very sharp, yet 

 by reason of the hardness of the bone, many particles of them are broken and 

 squeezed together, so as the mouths of the little tubes are closed up. A third 

 sort, much larger than the former, had also their mouths scarcely discoverable; 

 but I found them placed in such order, as convinced me, that the ring of these 

 tubuli was the augmentation of the bone, as I had formerly discovered it to be 

 iq wood, especially when I saw, at a little distance, another circle or ring of 

 tubuli. A forth sort exceeded the former very much, and were fewer ; so 

 that in the space of three or four sands I scarcely found one of them. 



Besides the above-mentioned four sorts of tubes, running the lengthways of 

 the bone, I sometimes imagined I saw some in a contrary situation, which 

 seemed to proceed from the middle of the bone, and terminate at the circum- 

 ference ; and that these were of two sizes. Some of these seemed as if perfo- 

 rated by those that run lengthwise. I suppose the periosteum is mostly con- 

 stituted and nourished by these ; especially as we see the same in trees, in which 

 the bark is formed by the transverse fibres that run from the centre, passing 

 between the direct ones. I conceive that the membranes surrounding the 

 bones have their increase from some vessels proceeding from the cavity of the 

 bone of the circumference, where they are dilated into that thin soft skin, 

 defending the bone, as the bark does the tree. 



I know many believe the origin and nourishment of the bark is from the root; 



VOL. III. 4 C 



