V. THERMOMETRIC. 943 



10 inches to 6 inches, then to 4 inches, and to 3 inches. From that time 

 the use of the clinical thermometer has rapidly extended, until now it is found 

 in the pocket of almost every medical practitioner. 



3745b. Clinical Chart Forms for temperature, &c. 



Harvey ', Reynolds, $ Co. 



Quarto size for hospitals ; octavo size for medical practitioners and their 

 patients. Designed by Edward Casey, M.D., Windsor. 



3745c. Registering Clinical Thermometers for the 

 Pocket. fg . r Harvey, Reynolds, $ Co. 



The clinical thermometer, as introduced by Dr. Aitken, was made of the 

 length of 10 inches. It was seldom used beyond the walls of a hospital, from 

 its want of portability. In the year 1867, Dr. Clifford Allbutt, of Leeds, re- 

 quested the exhibitors to make for him a thermometer of the length of 6 

 inches, the reduction in the length of the stem being compensated by making 

 a small chamber in the bulb. This served for the retreat of the mercury at 

 temperatures below 90 Fahr. 



Instruments of the length of 4 inches and 3 inches were subsequently 

 made, and the result of this portability has been the universal adoption of 

 the clinical thermometer in medical practice in Great Britain. Beyond this, 

 physicians often direct patients to be guided by its indications as to when to 

 send for medical advice. 



3746. Standard Thermometer, for physiological purposes , 

 0-50, divided into ^ (Virchow). 



Ch. F. Geissler $ Son, Berlin. 



3747. Standard Thermometer, for physiological purposes, 

 '30-45 (Heidenhain). Ch. F. Geissler $ Son, Berlin. 



3748. Two Pocket Maximum Thermometers, for the use 



of physicians, in a case and ebonite sheath. 



Ch. F. Geissler $ Son, Berlin. 



3749. Geissler's Standard Thermometer, for determining 

 the temperature of the skin, divided into y 1 ^ . 



Ch. F. Geissler $ Son, Berlin. 



3750. Geissler's Standard Thermometer, for determining 

 the temperature of the ear. Ch. F. Geissler fy Son, Berlin. 



3751. RosenthaPs Electrical Thermometer, for deter- 

 mining animal heat. Constructed by Dr. A.-Lessing, of Nurem- 

 berg, f-jjk f >r f' Rosenthal, Erlangen. 



The electro-thermometer consists of a bundle of iron and German silver 

 wires, which is contained in an elastic catheter, and can be easily introduced 

 into any cavity of the body. It serves for the measurement of the tempera- 

 ture of the body in different places, and especially for lecture demonstrations. 

 The resistance of the exhibited example = 0-25 Siemens' units. For intro- 

 duction into the heart, e.g., by the jugular vein, a smaller sized instrument 

 must be used. 



