V. THERMOMETRIC. 797 



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. 



3752. Circulation Thermometers, in pairs, 12" long, 

 divided from 35 to 45 centigrade. T. Hawksley. 



3752a. Dupre's Thermometer, with spiral bulb and silver 

 reflector, for ascertaining the temperature of the surface of the 

 body. T. Hawksley. 



3752b. Fair of Clinical Thermometers. 



E. Cetti $ Co., London. 



3752c. Three Clinical Thermometers, in cases. 



E. Cetti $ Co., London. 



3752d. Two Page's Regulators. E. Cetti fy Co., London. 

 3752e. Giessler's Regulator. E. Cetti $ Co., London. 



VI. APPARATUS FOR INVESTIGATING THE 

 FUNCTIONS OF CIRCULATION AND RESPIRATION. 



3753. Model of Hermann's Heart Fump. 



Professor Dr. L. Hermann, Zurich. 



This apparatus, exhibiting the use of the auricle, may be applied in con- 

 nexion with Weber's model of the circulation of the blood. The auricle (the 

 narrow chamber of the pump), without entrance valve, works in such a 

 manner that the heart receives blood from the veins both during the systole 

 and the diastole of the ventricle (the wide chamber). When the play of the 

 auricle is prevented, by shutting off its piston from the lever, the heart receives 

 blood only during the diastole of the ventricle. 



3754. Apparatus for Artificial Respiration. 



Professor Strieker, for the Institute for General and 

 Experimental Pathology, Vienna. 



The apparatus consists of clockwork set in motion by two steel springs, 

 each five centimetres wide, and 598 centimetres long. The clock moves 

 bellows, through which an animal, narcotized for the experiment, can receive 

 sufficient air to maintain circulation. 



To give the clockwork (made by Siegfr. Marcus, of Vienna) a uniform 

 movement, Professor Strieker has constructed a regulator the principle of 

 which is that with increasing velocity in the rotation of a balance wheel, two 

 rods are thrown from the plane of the wheel, which act against a brush and 

 so diminish the velocity. As the position of the brush can be regulated, the 

 checking of the velocity can be commenced at any time within certain limits. 



The clockwork can be made to work the bellows from 12 to 160 times per 

 minute. 



