The Coagulation Time of the Blood in Man 



317 



to keep them at a constant temperature. This gave an almost constant 

 temperature, and the variations are seen to be smaller. 



<i> 



•S ^ Fio. 4. — Diagram showing the coagulation time of the 



a .2 blood of a normal person taken at different periods 



•2 g of the day. M'Gowan's method, modified by 



3 's the addition of an apparatus for maintaining a con- 



§0 (3 stant temperature. The temperature wp.s approxi- 



o "" mately 20° C. throughout. 



^— — -• 



, ^ *^ ■ — 



10 11 12 



8 Hours of 

 the day. 



by my 



The coagulation times in the next chart (fig. 5) were taken 

 method, in which the temperature is kept absolutelj' constant. 



Here the variation is still less, and is due entirely to other experimental 

 errors (see Daily Variations in the Coagulation Time, Section IV.). 



E 



O 3 



-is 



Fig. 6. — Diagram showing the coagulat.jn time of 

 the blood of a normal person taken at different 

 periods of the day (Addis' method). The tem- 

 perature of the oil was maintained absolutely 

 constant at 18-5° C. 



^r^^'^—^-^—'- 



10 



8 Hours of 



the day. 



The following is a list of coagulation times taken by my hiethod at 

 temperatures between 10° C. and 20° C, which may be looked on as the 

 extremes of ordinary room temperature : — 



Temperature. Coagulation time. 



It is thus clear that variations of room temperature have a very great 

 effect on the coagulation time, and it follows that methods in which the 



