125 



BLOOD PRESSURES IN MAN, NORMAL AND PATHOLOGICAL 317 



may be concerned (e.g., in hypertension associated with the meno- 

 pause, etc.) the search for such pressor agents has failed to elucidate 

 the problem, proving almost barren of results. When kidney involve- 

 ment is also present there are the further undecided possibilities of 

 3, defective elimination, and 4, the genesis of pressor agents by ihe 

 damaged renal tissues. 



Mosenthal (98) concluded that high or low protein diet does not 

 increase or lower high blood pressures; similarly Newburgh (102) and 

 Squier and Newburgh (118) found high protein feeding ineffective, 

 though acting as a kidney irritant. On the other hand the observa- 

 tions of H. J. Starling (119), bearing on tuberculous cases, indicate a 

 definite elevation of pressure under the continued influence of an 

 abundant meat diet. An important point is raised by the finding 

 of Foster (48) that a reduction of blood pressure under the influence of 

 a continued low protein diet may take two months to develop; this 

 suggests that some negative conclusions with high or low protein diets 

 may possibly be due to periods of insufficient duration being studied. 

 Orr and Innes (105) observed a decided lowering of pressure after the 

 drinking of large quantities of water; they suggested a washing out 

 of metabolites as a probable cause of this effect. 



On the other hand Strouse and Kelman (121), examining cases of 

 raised pressure associated with various degrees of renal damage, found 

 that high protein diet caused no rise of blood pressure and that diminu- 

 tion of the protein intake in cases of definite nephritis, while lowering 

 the non-protein N of the blood, did not lower the pressure. Sudden 

 variations of systolic pressure sometimes amounting to 60 mm. were 

 often seen, attributed to emotional causes acting directly on the vaso- 

 motor centre; these variations were not affected by alterations in 

 protein intake. 



Salt has been surmised to have some relation to high blood pressure 

 and this hypothesis has influenced treatment, as in Allen's regimen with 

 a salt intake cut down to 0.5 gram per diem. The recent work of 

 O'Hare and Walker (103) lends no support to such a view. No rela- 

 tion was found to hold between the blood pressure and the chlorides 

 of blood and plasma, and no effect on the systolic and diastolic levels 

 was seen during wide variations in the amounts (0.5 to 4 grams) of 

 salt taken in high pressure cases without nephritis. Further in sub- 

 acute nephritis with edema and maximum salt retention comparatively 

 low pressures were often recorded. 



Cholesterin has also been suspected, especially by some French 



