THE FEMALE GENERATIVE ORGANS 539 



It is clear, therefore, that a spinal lesion in the lumbar region 

 may result in materially weakening the action of the uterus, 

 and so may hinder the normal course of labour. On the other 

 hand, in those cases in which the lesion was in the dorsal part of 

 the cord, the possibihty of spinal reflexes in the lumbar region 

 could not be excluded.^ 



The following general conclusions regarding the nervous 

 mechanism of parturition are based largely on those of Routh. 

 (1) The act of parturition is partly automatic and partly reflex, 

 these actions corresponding in the main to the first and second 

 stages of labour respectively, the spinal reflexes usually com- 

 mencing as soon as the membranes have ruptured. (2) Direct 

 communication with the brain is not essential for the proper 

 co-ordination of uterine action, but the brain appears to exercise 

 a controlhng influence of some kind. Thus, emotions often 

 become a hindrance to the progress of parturition. It would 

 seem possible that this inhibition of uterine contractions 

 is brought about by an inhibition of a centre in the brain 

 (see above, p. 530). (3) Direct communication between the 

 uterus and the lumbar region of the cord, is generally essential 

 for the occurrence of those rhythmical contractions which take 

 place during the progress of normal labour. There is experi- 

 mental evidence upon animals, however, that the uterus is some- 

 times able automatically to expel its contents, at least as far 

 as the relaxed portion of the genital cord, even when entirely 

 deprived of all spinal influence.^ 



Changes in the Maternal Organism 



The influence of parturition upon the metabohsm of the 

 maternal organism is dealt with by Sellheim.'^ There is a 



1 Konth also discusses post-mortem parturition, but points out that in 

 most of those cases where it occurred, the expulsion of the foetus was caused 

 by increased abdominal pressure due to putrefactive gaseous distension 

 during a condition of muscular relaxation. There are some facts which 

 go to prove that uterine contractility and retraction may continue or even 

 commence after death, possibly resulting from the movements of the 

 imprisoned child. 



^ For further references to the literature of the nervous mechanism of 

 parturition, see Bechterew, Die Funktionen der Nervencentra, Weinberg's 

 German translation, vol. i., Jena, 1908. ' Sellheim, loc. cit. 



