376 



PSYCHOLOGY. 



shows the way in which the pulse of one subject was 

 modified by the exhibition of a red light lasting from the 

 moment marked a to that marked b. 



Fig. 82. 



The effects upon respiration of sudden sensory stimuli 

 are also too well known to need elaborate comment. We 

 * catch our breath ' at every sudden sound. We * hold our 

 breath ' whenever our attention and expectation are strongly 



Fig. 83.- Respiratory curve of B: «, with eyes open: 6, with eyes closed. 



engaged, and we sigh when the tension of the situation is 

 relieved. When a fearful object is before us we pant and 

 cannot deeply inspire ; when the object makes us angry it 

 is, on the contrary, the act of expiration which is hard. 

 I subjoin a couple of figures from Fere which explain them- 



