MEDICAL BATTERIES. 59 



10,000 B A units in circtiit, gave 13° deflection. 

 5,000 „ „ 23° 



3,000 „ „ 33° 



2,000 „ „ 41° 



1,000 „ „ 55° 



500 „ „ 63° „ 



300 „ „ 66° „ 



100 „ „ 70° 



This table may give a hint to the operator, in what degree the resistance of 

 more or less of the human body influences the effective strength of the 

 battery, although it must be borne in mind that the human body has a very 

 variable resistance. 



The Becker-Muirhead Battery has been in use at the National Hospital for the 

 Paralysed and Epileptic, and in my own private residence for several years.^ 

 With ordinary watchfulness of its state of action, and care as to regularity 

 in re-charging and cleansing, it has proved a very effective and trustworthy 

 instrument. For a fixed, large surface, constant-current battery, it is the 

 form best fitted, to the present, to meet the wants of the English practitioner. 

 For, from the large extent to which IMuirhead's battery is used for the electric 

 telegraph in the kingdom, Uttle difficulty is experienced in making good 

 accidental damage, or necessary deteriorations, at a reasonable cost. More- 

 over, from the simplicity in detail of the instrument, it can be cleaned, 

 re-charged, and repaired with facility by a person of ordinary intelligence — 

 H. T.-] 



C. — Portable haUeries of small surface. 



In order to diminisli certain inconveniences of the batteries of 

 large surface, instruments have been designed composed of a great 

 number of small elements, which can be combined within a narrow 

 compass ; and which, in little bulk, possess sufficient electro-motor 

 power, without our having to fear too great calorific or electrolytic 

 action. 



I proceed to give a description of several forms of these small 

 electro-motor instruments, which constitute a real progress as 

 regards their therapeutical .application in certain cases ; although 

 they are, for the most part, far from combining all the conditions 

 that are to be desired. 



(a). Gaiffes portable battery of chloride of silver. — M. A. Gaiffe, 

 favourably known by the ingenious arrangements of his instruments 

 for medical electricity, has sent me a description, or rather a 

 detail, of a portable batteiy of constant continuous current that 

 he has constructed. It is the chloride of silver battery of MM, 

 Marie-Davy, E. Becquerel, and Warien de la Kue ; who, at dif- 

 ferent times, have made communications with regard to it. The 

 original idea belongs to M. Marie'-Davy ;^ and M. Gaiffe has 



* [In my own honse the battery is mental modes of jjacking, if such be re- 

 placed in a closet on the area floor, and the quired. Giving off no fumes or odours, 

 conducting wires with discs brought into it may be placed in any room without 

 the consulting-room. I may add, inci- hesitation, never becoming offensive. — 

 dentally, that this form of battery lends I H. 3'.] 

 itself very readily to ingenious and orna- ' ' See, for the method of re-chargiug 



