e^P 





810 



814 



Haemacytometer, Dr. Oliver's, consisting of lancet, standard graduated tube, and 10 



cubic millimetres measuring pipette . . . . . . eac h 212 6 



11 7 Haemacytometer and Lymphometer combined 



2 12 6 



f!2 T Haemodynamometer, Portable form for measuring arterial and venous blood pressure as 

 devised by Dr. George Oliver (latest pattern) with spring slide attached, in case, and 

 wristlet complete each 3 13 6 



The blood-pressure is obtained through the intervention of a stratum of fluid contained in a small cylindrical 

 investigation having demonstrated that the blood-pressure in man can only be accurately deter- 



- 



d through a fluid medium, a solid pad affording erroneous results because of the varying calibre of the 

 ptencs and of the different degrees of tissue resistance over them (see " Blood and Blood-pressure " bv U 



M.D., F.R.C.P., London : H. K. Lewis, 1901). 



The graduations, in mm.Hg., have been determined by the mercurial manometer. The scale in the form 

 a helix, or involved circles, comprises over 200 mm.Hg , and is of ample length, being at least n inches, to 

 ruble the observer to make accurate differential readings of 2^ mm. The instrument determines the blood- 



ssure in the arteries and in the veins. 



13 T Slide for applying Haemodynamometer . . 



each 



14' Sphygmomanometer (Tycos) after Dr. Rogers for determining both the Diastolic. and 



Systolic readings of Arterial blood pressure . . . . . . each 



The arm sleeve (Patent applied for), which contains the rubber bag for producing pressure upon the arm. 

 made of strong and inelastic but soft and flexible cloth. It is applied by placing the rubber bag directly 



the inside of the left arm, wrapping the sleeve, like a bandage, around the arm and tucking the end unclrr 

 ic preceding fold. The pressure produced by the inflating bulb catches the end of the sleeve, holding it tight 

 hile the observation is being taken. No straps or buckles are necessary. 



'Ihc rubber bag (gj by 5 inches), in the sleeve bandage is connected with the Sphygmomanometcr gautjr 

 1 with the inflating bulb by two small rubber tubes. A small hook, attached to the margin of the ban.!. 

 stains the gauge while the observation is being taken. The " Tycos " gauge measures pressure between 

 and j'io millimetre:-, of mercury. 



The ilial is graduated to centimetres, half and quarter centimetres, and, by an ingenious arrangement, is 

 cely movable, so that the index needle may always be adjusted to the zero of the scale without disturbing 

 '. hanism. 



I 



10 6 



500 



CHEMICAL AND SCIENTIFIC APPARATUS AND PURE CHEMICALS 



iff 



171 



