306 



F. R. BELL 



at the extreme dilution range possibly due to an effect on the whole animal 

 because of the disruption of its sodium economy. On the other hand the 

 threshold for salt taste may have been raised in the experimental animals 

 so that the receptors were unaffected by the dilute saline. 



THE EFFECT OF FEEDING Na'* SUPPLEMENT ON SALIVARY Nd^ AND \C CONCENTRATIONS 



9 lO 



DAYS _ 



G/IOOML NQHCOi 



INTAKE 30 



NaHCOj 



6 7 B 9 10 II 12 13 14 15 16 17 18 19 



NaHCO, 



INTAKE 



6 



n 



nn Rnn 



n 



Fig. 4. Shows the effect on salivary Na+ and K + when a sodium depleted calf 



is allowed the choice between sodium bicarbonate and water. (Bell and 



WilUams, unpublished data.) 



Behavioural changes become very obvious in calves made sodium de- 

 pleted through loss of saliva to the exterior. If salt from a tin is placed on 

 the ground or salt solutions are prepared within view of a sodium depleted 

 animal it will show much motor activity and become quite agitated and 

 make attempts to gain access to the saline material. A normal calf on the 

 other hand is indifferent to these procedures. Furthermore, if a sodium 

 deficient calf is allowed to select from a series of solutions which are known 

 to be sapid for calves contained in identical containers it will search until 



