No. XV.A.] APPENDIX. 225 



been magnetized, and, periaps, even a still smaller amount of steel might 

 in some cases be detected.* 



The batteries, electro-magnets, and magnetic needle, you may procure 

 of Messrs. Home, of Newgate Street ; or of Messrs. WiUats, of Cheapside ; 

 or, by order, of any other instrument-maker : but if you, or any of your 

 friends, meet with doubtful cases of this character, my own apparatus is 

 at your service, and I shall esteem it as a favour if you would allow me to 

 be present at the examination, in order that I may see the varieties which 

 different cases present. 



A centred magnetic needle should always accompany the ordinary 

 electro-magnets used for medical purposes ; as the medical pi'actitioner, 

 having that machine, might, with this addition alone, always determine 

 the presence of steel particles. 



Of medical electrical machines the primary coil machine may be 

 employed ; as the bundle of wires, when magnetized, will serve to mag- 

 netize the needle. The platinum spring machine may be employed 

 in a similar manner, and the bundle of wires in the rack machine may 

 also be used to effect the same object. In aU these cases you must 

 be careful to continue the voltaic cuirent in the same direction; for, if 

 you reversed the current but one instant, it would tend to undo what has 

 been abready done. 



I have now satisfactorily demonstrated to you, that magnetism may 

 be used for the detection of steel particles, impacted within the body, with 

 absolute success ; and, though but a very trifling application of natural 

 philosophy to the practice of surgery, I have no doubt that, had it been 

 adopted before, many joints would have been saved ; and I confidently 

 anticipate that it will be the means, in future, of frequently saving these 

 parts from destiniction. 



No. XV.A. 



AN ACCOUNT OF THE VARIOUS BREADS EXHIBITED 

 UNDER THE TITLE OP " FAMINE FOOD," at Mk. Smbe's 

 KBSiDEKCE IN FiNSBUET CiECXjs IN Februaet 1847. Taken from 

 sundry newspapers. 



The 'Morning Herald' states: "A very interesting collection of bread 

 in fourteen varieties was exhibited under the title of 'Famine Food.' 

 The rye, barley, and Indian com breads require no comment, from their 

 want of novelty. The root breads were respectively made of half of the 

 root previously boiled and reduced to a fine pulp, with half its weight of 

 wheaten flour. The yam bread was good, and much resembled potato 



* These weights are the nearest fractions, but we ascertained the exact weight 

 of these fragments by the standard balance belonging to the Bank of England : 

 these two portions amounted respectively to the -j^^ and the yjfo of a grain ; 

 the exact weight of the portion alluded to in the former part of the paper was 

 the 3^ of a grain. 



Q 



