660 



O. D. ANDERSON 



The C-R began to increase within a few days after the 

 vaginal bleeding ceased. The increased reflex persisted 

 throughout the period of the congestion in the external geni- 

 talia and for some time afterward, in some cases as long as 

 10 days after all external signs of oestrus had disappeared. 



Text-figure 115. Chart showing tlie effect of oestrus on the conditioned salivary 

 reflex in dog 881. Each bar drawn on the abscissa represents the magnitude of 

 the conditioned reflex (in 1/100 cc.) at a single presentation of the signal. Note 

 the great enhancement of the conditioned reflex during oestrus. 



PLATE 108 



EXPLANATION OF FIGURES 



1 A graphic record showing, in dog 881, the absence of the conditioned salivary 

 reaction in the interval between oestral periods to the Met. 120 followed by food. 



2 A graphic record showing the presence of a large and vigorous conditioned 

 salivary reaction to the same stimulus in the same animal (dog 881) during the 

 oestrus. 



3 A graphic record showing the conditioned motor reflex in dog 869 during 

 the last month of pregnancy. Note the small conditioned reaction (a single leg 

 movement). 



4 A graphic record of the conditioned motor reflex in the same animal (dog 

 869) during the period of lactation. Note the exaggerated motor reactions both 

 of the head and of the reaction leg to the signal. The reactions continue even 

 after the signal has ceased. 



5 A graphic record showing in dog 866 the normal conditioned salivary 

 response to Met. 120. 



6 A graphic record from the same dog (866) with the absence of the con- 

 ditioned salivary reflex following thyroidectomy. 



