AN ANATOMICAL STUDY ON THE 



who is lean, with large veins, warm after exercise 

 when more blood is going to the extremities and the 

 pulse is stronger, for then all will be more apparent. 



Under these conditions, place on a ligature as 

 tightly as the subject can stand. Then it may be 

 observed that the artery does not pulsate beyond 

 the bandage, in the wrist or elsewhere. Next, just 

 above the ligature the artery is higher in diastole 

 and beats more strongly, swelling near the ligature 

 as if trying to break through and flood past the 

 barrier. The artery at this place seems abnormally 

 full. The hand, however, retains its natural color 

 and appearance. In a little time it begins to cool 

 a bit, but nothing is "drawn" into it. 



After this bandage has been on for some time, 

 loosen it to the medium tightness used, as I said, 

 in blood-letting. You will see the whole hand at 

 once become suffused and distended, and its veins 

 become swollen and varicosed. After ten or fifteen 



experimental measurements reported in h\s Statistical Essays: Haamo- 

 dynamics, 1733. A valuable account of Hales has been given by 

 P. M. Dawson (Johns Hopkins Hosp. Bull., 15: 185, 232, 1904). 

 Further advance was made by J.-L.-M. Poiseuille (1799-1869), whose 

 haemodynamometer was introduced in 1828, and whose studies on 

 capillary flow appeared in 1840 (Compt. rend. Acad, sc, 11 : 961.1041). 

 In 1847 Carl Ludwig (1816-1895) invented the graphic method of 

 recording blood -pressure, and thus greatly facilitated all phases of 

 physiological analysis (Miiller's Arch. Anat. Physiol., 1847, P- ^4^)- 

 A method for determining venous pressure in man was devised by 

 J. A. E. Eyster and D. Hooker (Johns Hopkins Hosp. Bull., 19: 274, 

 1908). For a general disussion, see W. H. Howells' Physiology, loth 

 Ed., Phila., 1927, p. 475. Also Journ.Am. Med.Asso., 91: 31 (July 7) 

 1928. 



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