Accession No
6373
Brief Description
Electrite portable electrocardiograph (ECG), by Cambridge Instrument Company Ltd., English, 1950
Origin
England; Cambridge
Maker
Cambridge Instrument Company Ltd.
Class
medical; electrical
Earliest Date
1950
Latest Date
1950
Inscription Date
Material
wood; metal (3 types of white metal, steel, brass); plastic (bakelite, perspex, and at least 3 others); paper (card); hide (leather); rubber; paint
Dimensions
height 280 mm; width 224 mm; depth 335mm
Special Collection
Provenance
Inscription
‘CAMBRIDGE
ELECTRITE
CARDIOGRAPH
CAMBRIDGE INSTRUMENT CO LTD
LONDON AND CAMBRIDGE
C533765’
(Two metal plates, one on front of instrument and the other on the top of the recorder unit)
‘DR RYAN’
(Dymotape label on lid)
‘Customers Instrument
NOT TO BE TAKEN AWAY’
(Written in pencil on a strip of masking tape on top of box)
Description Notes
Electrite portable electrocardiograph (ECG), by Cambridge Instrument Co., England, 1950.
Wooden case with leather carrying handle, white metal hinges and lock (broken, no key). 4 power sockets on right hand side of case. Whole instrument set on 4 rubber feet with ventilation grilles on underside. Main instrument covered by black-painted metal plate with recording apparatus, with glazed window, mounted on left-hand side. Switches for ‘Stylus Heat’, ‘Sensitivity’, ‘Position’, ‘Off Record’, and ‘Standardize 1mV’. Also dial divided ‘0’, ‘1’, ‘2’, ‘3’, ‘aVr’, ‘aVl’, ‘aVf’, ‘V’, ‘CR’, ‘CL’, and ‘CF’ and marked ‘Leads’. Cable from rear of instrument passes up into lid of box to black box with 2 switches. Beneath this box are instructions for showing how to ‘Eliminate any interference on any lead’. Condensed instructions for use of instrument on main metal plate. Door on right-hand side of lid covers fitted compartment for accessories; tube of electrode jelly (in box) present. Dymotape label on lid ‘Dr Ryan’; also length of masking tape with pencil marking ‘Customer’s instrument not to be taken away’.
Incomplete
References
Events
Description
An electrocardiograph is a medical instrument that records the electrical activity of the heart. Physiologists discovered the electrical wave that accompanies the human heart beat at the end of the 19th Century and Dr Willem Einthoven designed an electrocardiograph using a string galvanometer to practically and precisely record it in 1903. It would eventually revolutionise the study of the heart and massively improve the treatment of heart disease. However, the original design was large and awkward - filling a room, weighing over 650lbs, and requiring patients to immerse their limbs in saltwater baths to transmit the heart's electrical current.
Dr Einthoven approached Cambridge Scientific Instrument Company to manufacture a marketable electrocardiograph and the Company proceeded with the redesign of the instrument. It completed its first full electrocardiograph in 1908. The Company continued to improve the electrocardiograph and make it smaller, but its design remained fundamentally unchanged for decades.
Cambridge Instrument Company released the Electrite model in the 1950s. It was the first valve-operated electrocardiograph in Britain. It was also the Company's first direct-writing instrument, with a heated stylus replacing the camera, making results instantly available. The Electrite was a better model than most other valve-operated electrocardiographs and it sold well.
25/03/2020
Created by: Morgan Bell on 25/03/2020
Description
Electrocardiographs are medical instruments that measure the rhythm of heart contractions and the relative strength of different parts of the heart muscle. This instrument produced recordings—cardiograms—using the direct writing method. An electrically heated stylus glided over the surface of the paper roll that was feed from a rotating drum. The heat of the stylus determined thickness of the deposited of ink. The oscillatory mechanism was standardized according to a timed electrical impulse that recorded as intervals on the paper. This way, the accuracy of the paper speed could be measured and verified. The first direct writing instruments used a d’Arsonval galvanometer that carried a writing point. They were initially developed and designed to record nerve impulses; however, Dr. Bryan Matthews who produced these instruments quickly recognized that this technology could be applied to cardiography. Matthews worked at the Physiological Laboratory in Cambridge. The subsequent models manufactured by The Clifton Instrument Company did not have much success, but designs by the Cambridge Scientific Instrument Company proved practical and marketable. This electrocardiograph was owned by a ‘Dr Ryan’ as inscribed on the lid label of the instrument.
06/11/2013
Created by: Allison Ksiazkiewicz on 06/11/2013
FM:43891
Images (Click to view full size):
