246 M. Dufrenoy's Description of Greenovite. 



with the views now generally entertained concerning the ori- 

 gin of fibres. 



" All the organic tissues," says Dr. Schwann, " however 

 different they may be, have one common principle of develop- 

 ment as their basis, viz. the formation of cells ; that is to say, 

 nature never unites molecules immediately into a fibre, a tube, 

 and so forth, but she always in the first instance forms a round 

 cell, or changes, when it is requisite, the cells into various 

 primary tissues as they present themselves in the adult state." 

 (Wagner's Physiology by Willis, p. 222.) 



How is the origin of the fibrils which I have depicted in so 

 many varieties of fibrine to be reconciled with this doctrine ? 

 And what is the proof that these fibrils may not be the pri- 

 mordial fibres of animal textures? I could never see any 

 satisfactory evidence that the fibrils of fibrine are changed 

 cells; and indeed in many cases the fibrils are formed so 

 quickly after coagulation, that their production, according to 

 the views of the eminent physiologist just quoted, would hardly 

 seem possible- Nor have I been able to see that these fibrils 

 arise from the interior of the blood-discs, like certain fibres 

 delineated in the last interesting researches of Dr. Barry. 



I have to express my acknowledgements to Dr. Dumbreck, 

 Surgeon 72nd Regiment, and to Dr. Boyd, Resident Physi- 

 cian to the Marylebone Infirmary, for their kindness in afford- 

 ing me opportunities of examining the cases just mentioned; 

 and to Mr. Siddall for calling my attention to the state of the 

 blood in the cases noticed in the last Number of the Philoso- 

 phical Magazine. 



XLIII. Description of Greenovite. By M. Dufrenoy*. * 



ly/T DUFRENOY states that this mineral, so called in 

 • honour of G. B. Greenough, Esq., is a titaniate of 

 manganese, and except crichtonite, which is a titaniate of iron, 

 is the only one hitherto described. It was discovered by M. 

 Bertrand-de-Lom in the manganese deposit of Saint Marcel, 

 in Piedmont; it occurs in small rose-coloured veins which 

 run irregularly in the mass, and is accompanied by quartz, 

 epidoteand manganesian garnets. It was supposed originally 



Fig. 1 . Fig. 2. 



o 



* From the dnnafes drs Mines, vol. xvii. 



