340 



IMPROVED SCARIFICATOR. 



Use of the sca- 

 rificator. 



V. 



Description of an improved Scarificator : by Mr. John 

 Fuller. No. 14, Hatton-Garden *. 

 SIR, 



1 WISH to submit to the notice of the society an improve- 

 ment in the construction of the scarificator, which I flatter 

 myself will be found worthy their attention. It may be 

 necessary to premise, that the scarificator is an instrument 

 used in cupping for making the incisions, from which 

 blood is afterward obtained by means of exhausted glasses. 

 As the degree of pain caused by this operation depends on 

 the good or bad quality of the scarificator, this instrument 

 has always been an object of attention. The best scarificators 

 generally in use propel from ten to sixteen lancets, through 

 about half a circle, which is effected by a part, termed the 

 rack, moving on its centre or part of its edge. On part of 

 its edge are situate teeth, which are so confined that by 

 moving the cock or tail of the rack, they work three pinions, 

 and make them revolve about halve a round : it is evident, 

 that lancets fixed on the axis of these pinions must also have 

 a circular motion, and endeavour to cat any thing opposed 

 to their passage; it is likewise evident, that, if a spring be 

 so set, that it can be released, and its force applied on a 

 sudden to the rack, (somewhat similar to the main-spring 

 of a gun-lock) all the lancets will be carried forward at 

 once, and that with a force and velocity in proportion to 

 the strength of the main-spring. 



The objections to this construction, which frequently oc- 

 cur in practice are, that from the number of lancets neces- 

 sarily used, the resistance to their motion is so great, that 

 that they do not move with the swiftness requisite to the ease 

 of the patient; it is likewise often desirable to have the in- 

 cisions rather deep, and then they arc often quite stopped in 

 their progress : bcsitle this, by the lancets all moving one way, 

 they are found to drive the skin up in folds, and thus pre- 

 sent additional resistance, and occasion excessive pain to 



* Trans, of the Soc. of Arts, vol. xxix, p. 126. The silver 

 medal was voted to Mr. Fuller for this improvement. 



the 



