BLOOD FLOW IN MAN. 



211 



hand to pass into the vessel. About an inch beyond the edges of this hole a 

 strip of copper, about 1 inch wide, is soldered at right angles to the lid. Besides 

 the hand-hole, and on the opposite side of the centre, three small circular holes 

 are made in the lid each about one inch in 

 diameter and provided with a copper 

 tube of similar diameter, projecting up- 

 ward. A piece of insulating cork is cut so 

 as to form a lid large enough to fit the 

 outer vessel, and holes are made in it to 

 fit the tubes round the openings in the 

 copper lid of the inner vessel. After fitting 

 the cork cover in place, it is covered with 

 varnish. The three small holes are used, 

 one of them for a thermometer, and the 

 others for long feathers to serve as 

 stirrers. A piece of thick saddler's felt 

 is cut to fit the hand opening in the lid. 

 Several collars of the same material are 

 also cut, 1 inch wide, and of various sizes 

 to fit wrists of different sizes. The felt 

 lid and collars rest on the copper ledge 

 between the head opening and the ridge 

 of copper. A thermometer with a 

 scale which reads between C. and 50 

 C. divided into l/10ths is sufficiently 

 accurate. By using a telescope the 

 temperature can be read to l/50th or 

 I/ 100th of a degree. 



Besides the calorimeter, a large bath 

 of 20 or 30 litres capacity (garbage can) 

 is necessary. It is also convenient to have 

 an adjustable stool (like a music stool) 

 on which to place the calorimeter. 



Demonstration 4. To make 

 the measurement, the first step 

 is to draw a line with a fat pencil 

 on the skin at the lower border of 

 the styloid process of the ulna of 

 the hand chosen for observation. 

 A felt collar of proper size is then 

 applied to the wrist with its lower 



border corresponding to the pencil line, and a second line is drawn 

 on the skin opposite the upper border of the collar. This upper line 

 will serve as a mark to show that the hand is not changed in position 



FIG. 64. Stewart's Calorimeter. 



