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Addis 



be screWed off and the length of the jet, as it issues from the stop-cock, is 

 measured in the same way : it should be 65 cm. In this way the location 

 of the obstruction can be ascertained. 



This does not need to be done before every estimation, but it should be 

 done every now and then, especially if the apparatus is not being constantly 

 used. Of course, any considerable variation in pressure .reveals itself, by its 

 different action on the blood. 



A temperature of 185° C. is a convenient one to work with. It 

 is easily maintained by regulating the temperature of the water in the 

 tank The correct temperature having been attained, it is advisable not 

 to stop the flow of oil by turning the stop - cock between successive 



Fig. 2. 



-Diagram of theinetal box with the truncated glass 

 cone removed. 



The thermometer (T) and the tube (t) are ahown piercing the side of . 

 the box ; the bulb of the thermometer and the nozzle of the tube 

 being inside the chamber. 



estimations, because it takes a little time for the box to be warmed up 

 again. 



The parts of the apparatus which come in direct contact with the 

 blood, i.e. the end of the glass cone and the instrument used for punctur- 

 ing the skin, have to be freed from any possible contamination with fibrin 

 ferment. 



The only way to do this with certainty is to expose them for some time 

 to a temperature above 65° C. At temperatures above that point, fibrin 

 ferment is destroyed. 



The puncturing instrument and the glass cone are placed in a vessel 

 full of oil, the lid of which has three holes cut in it. Into one of these a 

 thermometer is fitted, and through the other two the cone and lancet can be 

 hung, so that they dip below the level of the oil. The vessel is placed in a 

 tin of water, which is then heated until the thermometer indicates that the 



