122 



KICK'S FLAT SPRING-KYMOGRAPH. 



(B) In man the blood-pressure may be estimated by means of (1) a properly 

 graduated sphygmograph (J 67). The pressure required to abolish the movement 



of the lever indicates approxi- 

 mately the vascular tension. The 

 mean blood-pressure in the radial 

 artery is equal to 550 grams. 



(2) Sphygmomanometer of 

 v. Basch. A capsule containing 

 fluid was placed upon a pulsating 

 artery, while the capsule itself 

 communicated with a mercurial 

 manometer. As soon as the pres- 

 sure within the manometer slightly 

 exceeded that within the artery, 

 the artery was compressed so that 

 a sphygmograph placed on a 

 peripheral portion of the vessel 

 ceased to beat. Both arrange- 

 ments do not give the exact 

 pressure within the artery ; they 

 only indicate the pressure which 

 is required to compress the 

 artery and the overlying soft 

 parts. The pressure required to 

 compress the arterial walls, how- 

 ever, is very small compared with the blood-pressure. It is only 4 mm. Hg. 

 V. Basch estimated the pressure in the radial artery of a healthy man to be 135 

 to 165 millimetres of mercury. 



Variations. In children the blood -pressure increases with age, height, and weight. In the 

 superficial temporal artery, at 2 to 3 



years, it is - 97 nun. : 12 to 13 years, f gmmmmmmmmmmm 



113 mm. Hg. {A. Eckcrt, c. 100). M 



The blood-pressure is raised imme- 

 diately after bodily movements ; it is 

 higher when a person is in the hori- 

 zontal ]>osition than when sitting, and 

 in sitting than in standing. After a 



Fig. 104. 

 Kick's flat spring-kymograph. 



eold as well as after a warm bath, the first effect is an increase of blood-pressure and of the 

 quantity of urine. r 



85. BLOOD-PRESSURE IN THE ARTERIES. The following results have 

 been obtained by experiment on systemic arteries : 



(a) Mean Blood-Pressure. The blood-pressure is very considerable, varying 

 within pretty wide limits ; in the large arteries of large mammals, and perhaps in 

 man, it = 140 to 160 millimetres [5-4 to 6*4 inches] of a mercurial column. 

 The following results have been obtained, those marked thus * by Poiseuille, and those + by. 



Fig. 103. 

 Kirk's spring-manometer, as improved by Hering 



Carotid, Horse, 161 mm. 



122 to 214 mm. 

 ,, Dog, 151 mm. 



,, 130 to 190 mm. {Lxidvit,). 

 Goat, 118 to 135 mm. 

 Rabbit, 90 mm. 



Carotid, Fowl, 88 to 171 mm. 



Aorta of Frog, 22 to 29 mm. 



Gill artery of Pike, 35 to 84 mm. 



Brachial artery of Man during an opera- 

 tion, 110 to 120 mm. (Faivre). Per- 

 haps too low owing to the injury. 





