142 E. A SCHAFER. 



Postscript hy Dr. Sharpey. 



Dear Schafer, — As I know you are about to publish the 

 results of inquiries you have lately been making into the struc- 

 ture and growth of bone, I am induced to ask you to give a 

 place at the end of your communication to the following remarks 

 which I desire to make on a note addressed to the Accademia 

 Gioenia of Catania by Dr. Clementi, professor in the university 

 of that city, purporting to show that the " perforating fibres of 

 bone/' to which I drew attention in 1856, had been previously 

 described by two Italian writers on the structure of bone, 

 Domenico Gagliardi and Michael Troja.^ 



Gagliardi's work, entitled ' Anatomes Ossium, Pars prima ' 

 (no second part followed), was published at Home in 1689, and 

 his views on the structure of bone have often been referred to by 

 anatomists since his time. He considered that the compact 

 tissue of bone has a foliated structure, which becomes aj)parent 

 in bones — especially the tabular bones of the skull — which have 

 undergone desquamation by long exposure to the weather. The 

 layers into which they are thus resolved, "squamulae or bractese," 

 are coarse and rugged, and not to be confounded with the tine 

 lamellae now recognised by aid of the microscope, and Gagliardi 

 describes them as traversed by little osseous nails or pegs — 

 "claviculi" — which pin them together. These nails are held by 

 Dr. Clementi to be identical with the perforating fibres which I 

 have described. 



Now, it is not easy to say what these claviculi really are; 

 probably, as suggested by Sappey, they may be little rolls of 

 concentric Haversian lamellae, which become dislodged from their 

 place ; but, whatever be their nature, it is to be noted that they 

 are comparatively large objects, represented by Gagliardi as 

 visible to the naked eye in a figure he gives of a cranium (Tab. i, 

 tig, 1), reduced to a third of tlie natural size, and no more com- 

 parable to the perforating fibres than a broomstick is to a 

 bristle. 



With greater justice, however inconsistent with his notion 

 concerning Gagliardi's nails, Dr. Clementi next refers to passages 

 to be found in a work of the Neapolitan surgeon, Michael Troja, 

 which really prove that the perforating fibres had been recognised 

 by that eminent Italian professor. Troja, in the last century, 

 acquired well-merited distinction on account of his admirable 

 experimental ' Essay on the Ilegeneration of Bone,' published 

 at Paris, in Latin, in 1775, and afterwards in Italian, with im- 

 portant additions, at Nai)les in 1779. After having been many 



' LaScoperta dclle fibre dello Sliarpey rivendicata all' Italia. Nota 

 del Uottor Gesualdo Clementi, Professore paricrpiale di Patologia speciale 

 chirurgia, &c., nclla R. Uuiversita di Catania, 1875. 



