456 Royal Society. 



capillary copper and of variegated copper ore, instead of the magnetic 

 pyrites found in some meteoric iron ; and, lastly, by the presence, 

 though only a trace, of sulphuret of silver. 



Professor Stromeyer then enters into an examination of the circum- 

 stances which appear opposed to the opinion which assigns a meteoric 

 origin to this iron, and of the objections against its being the product of 

 artificial fusion j among which, one of the greatest is its considerable 

 alloy of molybdenum, — a metal which has hitherto not been observed 

 either in ores of iron and copper, or in any slags or other products of 

 smelting furnaces. But Dr. Stromeyer has since obtained, from the 

 Hartz Mountains, a similar and equally problematical mass of iron, the 

 analysis of which has furnished nearly the same results as that of the 

 Magdeburg iron, except that it contained no variegated copper ore. 

 Future observations will probably throw more light upon the nature of 

 these enigmatical metallic bodies ; at all events, the discovery of mo- 

 lybdenum in them is so far of great interest, as, in case they should 

 ultimately prove to be artificial products, it is fair to conjecture that 

 that scarce metal must enter into combinations still unknown to the 

 chemical mineralogist, or occur in some ores in a masked state and 

 such small proportions as to become (like titanium) apparent only irt 

 the products of the long-continued operations of the smelting fur- 

 nace. 



The following papers were read : — 



1 . "Observations on the Physiology of the Nerves of Sensation, il- 

 lustrated by a case of Paralysis of the Fifth Pair." By John Bishop, 

 Esq. Communicated by P." M. Roget, M.D., Sec. U.S. 



2. " On the Respiratory Organs of the Common Leech (Hirudo offi- 

 cinalis, Linn.), and their Connexions with the Circulatory System." 

 By George Newport, Esq. Communicated by P. M. Roget, M.D., 

 Sec. R.S. 



The stomach of the leech has been hitherto described as a large 

 elongated sac, simply divided into ten compartments by perforated 

 membranous partitions : but the author, by a more accurate exami- 

 nation, finds that each portion of that organ rs expanded into two 

 lateral caeca, which increase both in size and in length as they are 

 traced along the canal towards the pylorus. The cseca belonging to 

 the tenth cavity are the longest, extending as far as the anus, and 

 have themselves four constrictions : the cavity itself terminates in a 

 funnel-shaped pylorus. When the posterior end of the animal is cut 

 off, the caecal portions of the stomach are laid open, and the blood 

 which it receives flows out freely, as fast as it is swallowed ; and 

 hence the leech, under these circumstances, continues to suck for an 

 indefinite time. 



The respiratory organs consist of two series of pulmonary sacs, ar- 

 ranged along the under side of the body, on each side of the nervous 

 cords and ganglia. They each open upon the surface of the body by 

 a very minute but distinctly valvular orifice. The membrane which 

 lines them appears to be continuous with the cuticle, and is exceed- 

 ingly delicate and highly vascular, receiving the blood, for the purpose 

 of its being aerated, from the veins of the system. The blood is re- 

 turned from these sacs into the lateral serpentine vessels by vessels 



