PREGNANCY AND PARTURITION 1383 



NERVOUS MECHANISM. We possess little experimental know- 

 ledge of the nervous mechanism of parturition. The most important 

 observation on this point is the already quoted experiment by Goltz, 

 in which this physiologist observed the normal performance of menstrua- 

 tion (heat), impregnation, and parturition in a bitch whose spinal 

 cord had been completely divided in the dorsal region during the 

 previous year. On the other hand, destruction of the lumbo -sacral 

 cord completely abolishes the normal uterine contractions of parturi- 

 tion, so that this act must be regarded as essentially reflex, presided 

 over by a controlling ' centre ' in the grey matter of the cord. The 

 activity of the centre can be inhibited or augmented by impulses 

 arriving at it from the peripheral parts of the body, as by the stimu- 

 lation of sensory nerves, or from the brain, as under the influence of 

 emotions. The nerve-paths from the centre to the uterus have been 

 already described. 



