Blood Pressure Instrument 



295 



centrifuged and the sediment is resuspended in a measured 

 volume of water or salt solution. This is not true of the so- 

 called synthetic media which contain no protein substances. 



Demonstration of an instrument for taking repeated blood pres- 

 sures in rabbits, with report of some experiments. 



[From the University of Minnesota, Minneapolis, Minnesota.] 



In connection with a study of renal insufficiency in rabbits, 1 

 it became desirable to take a series of blood pressures on the 

 animals. An instrument has been perfected by means of which 

 the blood pressure can be taken in the central artery of the ear. 

 The instrument is composed essentially of three parts; namely, 

 a pressure piece, a "U" tube containing mercury, and a rubber 

 bulb with which to make pressure. 



The pressure piece is made of glass. It is composed of an 

 open cup (1) (see drawing) an apposing smooth, slightly con- 

 vex stage (2), a connecting curved arm (3), and a short glass 

 point (4) by means of which the cup may be connected with 

 the "U" tube. The mouth of the cup is covered by a rubber 

 membrane (5) which, when pressure is made within the cup, 

 bulges against the stage. The rabbit's ear is slipped between 

 the stage and rubber membrane. The stage contains a light 



1 To be reported at a later date. 



144 (2104) 



By H. C. ANDERSON (by invitation). 



