800 SEC. 18. BIOLOGY. 



Two other similar signal apparatus serve in connexion with two differently con- 

 structed electric double keys for marking the beginning or end of the electric 

 shocks, or other effects. The rapidity of the movement of the blackened 

 paper is variable within wide limits. 



3765. Apparatus for Artificial Inspiration and Ex- 

 piration. Physiological Institution, Prague. 



Two pumps working synchronously, one of which is devoted to inspiration, 

 the other to expiration. The number and depth of the respiratory acts are 

 variable within wide limits. The apparatus allows also the employment of 

 mixtures of gases and the preservation of the air expired without any loss. 



3766. Portable Injection Apparatus, with constant pres- 

 sure, for artificially filling the blood and lymph vessels. 



Physiological Institution, Prague. 



By means of this apparatus every pressure between 2 and 300 mm. of 

 mercury can be produced, and it remains unaltered during the whole con . 

 tinuance of the injection. The apparatus may be used for the simultaneous 

 injection of two groups of vessels. 



3767. Scheme of the Circulation. 



Physiological Institution, Prague. 



The apparatus consists of two glass cylinders, communicating by a horizontal 

 tube, one representing the arterial, the other the venous, system. In the 

 horizontal tube there is, in imitation of the capillary system, a sponge, in 

 which the resistance to the current may be diminished or increased at will 

 by means of a screw. A small pump brings the fluid with the desired force, 

 or in the desired quantity, from the venous into the arterial system. 



3768. Gassphygmoscope, by Sigismund Mayer. 



Physiological Institution, Prague. 



The apparatus consists of a small drum or capsule placed on the skin above 

 a beating artery, through which common coal gas is allowed to flqw towards 

 a flame. Each pulsation causes a contraction of the flame, and shows, among 

 other things, very plainly the dicrotism of the pulse. 



3769. Apparatus for the Registration of the Respi- 

 ratory Movements. Physiological Institution, Prague. 



The above consists of an air-tight case containing a living animal, which 

 breathes through a tube fastened in the trachea. This tube communicates 

 with the atmosphere through the side of the chest. The air enclosed in the 

 chest is moved in oscillations of pressure by the breathing of the animal, and 

 these oscillations are registered on the kymographion. 



The apparatus allows at the same time the registration of the pressure of 

 the blood, the section of the nervi vagi, the irritation of any desired nerves, 

 and the injection into the jugular vein, without opening the case. 



3770. Apparatus for Registering the Respiratory 

 Movements. Physiological Institution, Prague. 



In this apparatus the animal breathes out of a large air-tight closed receiver, 

 which communicates with the trachea by a tube. The changes in the pressure 

 of the air in the receiver, thus produced, are shown on the kymographion. 

 The air in the receiver is frequently renewed. 



