LABOUR. 51 



contraction of the muscular fibres, which enter into the composition 

 of the uterine parietes. By this contraction the cavity of the uterus 

 is diminished in size, propulsion is produced, and eventually expul- 

 sion is effected. The action of the uterus continues even after the 

 child is expelled, for the purpose of extruding the placenta, and 

 closing the orifices of bleeding vessels, which might otherwise give 

 rise to serious hemorrhage. 



The classification of labours. — Almost every obstetrical writer has 

 a classification in accordance with his own peculiar views, each 

 based upon his definition of a natural labour. Some include under 

 the head of natural labour, all those cases which are terminated by 

 the natural unassisted powers, without reference to the presentation. 

 Among these are Hippocrates, Smellie, Baudelocque, Rigby, &c. 

 Others consider that the presentation should be taken into account, and 

 those only which occur most frequently should be called natural. 

 Denman, Blundeil, Davis, Ashwell, Ramsbotham, &c., therefore 

 limit natural labours to head presentations. 



The simplest classification seems to be that which includes all 

 under two heads, viz. : natural^ and preternatural. Natural labour, 

 or eutocia, being that which follows a natural course, and in which 

 the woman is delivered unassisted ; 'preternatural labour, or dysto* 

 cia, signifying faulty or irregular labour, the course of which is 

 unfavourable, and in which the assistance of the obstetrician becomes 

 necessary. 



The general features of labour are the same in every case, but 

 the details are widely different. It is always attended with suffering, 

 if the patient be conscious ; and is sometimes complicated with irregu- 

 larities and danger. The duration also varies much, as well as the 

 amount of pain, in different women, and in the same women in dif- 

 ferent pregnancies, some expelling their children with a single pain, 

 others requiring many to accomplish the same object. 



The symptoms of labour may be divided into the premonitory, 

 and those which indicate that the process has already commenced. 

 The premonitory are, the subsidence of the abdominal tumour ; some 

 slight mucous discharge from the vagina, together with relaxation 

 and distensibility of it and the external parts ; and a peculiar irrita- 

 bility and restlessness on the part of the patient. 



The diminution of the abdominal tumour is produced partly by the 

 subsidence of the uterus into the pelvic cavity, and partly perhaps 

 by the painless contraction of the same organ. It is sometimes very 

 sudden in its approach, the woman finding on rising from her bed 

 that she is much less than on the preceding day. It is generally a 

 good sign, as indicating that she has a roomy pelvis. The increased 

 discharge and relaxation of the external organs is also a good sign, 

 showing that there is a disposition in the passages to facilitate the 

 progress of the labour. 



