66 



J0RN Hess Thaysen 



are present in parotid saliva and in sweat in sufficiently large 

 concentration to make up for this difference. Judging from the 

 results of Table I, the production of sweat and parotid saliva 

 should therefore involve secretion of hypotonic precursor 

 solutions, a process which a priori does not appear very likely. 



• y» 0.112(t0.005)X-2.4(tO.A) 



20 



40 



60 



100 



120 



X«SECRETORY RATE (mg/gram gland /min) 



Fig. 2. The relation between the rate of sodium 

 excretion in parotid sahva (in microequivalents 

 per gram gland per minute) and secretory rate (in 

 milligrams per gram gland per minute). The linear 

 regression has been calculated for all data at or 

 above a secretory rate of 60 milligrams per gram 

 gland per minute. 



It must be emphasized, however, that the calculated figures 

 for precursor sodium concentration (and sodium reabsorp- 

 tion) in the sweat and parotid glands underestimate actual 

 values, since the regressions for sodium excretion on secretory 

 rate have been fitted to points which approach, but do not 

 reach, a rectilinear relationship within the observed range 

 (cf. Fig. 2). One explanation for this considerable splay in 



