980 OF GENERATION. 



for some time after somatic death, when neither the Cerebro-spinal nor the 

 Sympathetic system can afford any supply of nervous power, is yet a more satis- 

 factory proof of the same position. Nevertheless, it seems quite certain that 

 muscular contractions of the uterus may be induced by reflex action ; for in no 

 other way can we account for numerous phenomena, which distinctly mark the 

 operation of remote causes acting through the nervous system, such as the in- 

 duction of uterine contractions by the dash of cold water on the abdominal sur- 

 face, by the injection of cold water into the vagina, by the ingestion of cold 

 water into the stomach, or even by dipping the hands into cold water, or again 

 by the suctorial application of the infant's lips to the nipple, by the introduction 

 of the hand into the vagina, by violent movements of other parts of the body, 

 and by various other means. This general fact has an important practical 

 bearing ; since there are various occasions on which it is most important to life, 

 that the previously flaccid uterus should be excited to vigorous contraction, for 

 the sake of accelerating parturition or of suppressing hemorrhage ; whilst, on 

 the other hand, it is often no less important to be able to prevent or to antago- 

 nize the operation of causes which would prematurely induce uterine contrac- 

 tions, to the destruction of the offspring and the danger of the mother. When, 

 in the normal act of Parturition, the head has so far made its way through the 

 os uteri as to begin to distend the lower part of the genital canal, a new kind of 

 expulsive effort is superadded to that of the uterus itself; the assistance of the 

 Expiratory muscles being then called in ( 723), through the intermediation of 

 the Spinal Cord, which is probably excited to this action by the stimulus thus 

 applied to the afferent nerves of the compressed parts; and it is chiefly by the 

 instrumentality of these muscles, that the normal act of parturition is usually 

 completed. The same action which expels the foetus also detaches the placenta; 

 and if the uterus contract with sufficient force after this has been thrown off, 

 the orifices of the vessels which communicated with it are so effectually closed, 

 that little or no hemorrhage takes place. If, however, the uterus does not con- 

 tract, or relaxes after having contracted, a large amount of blood may be lost 

 in a short time from the open orifices. For some little time after parturition, a 

 sero-sanguineous discharge, termed the lochia, is poured out from the uterus; 

 and this commonly contains shreds of the deciduous membrane, which had not 

 been previously detached, together with a quantity of fat globules, and of other 

 products of disintegration of the uterine tissue ( 593). * Within a few weeks 

 after delivery, the uterus regains (at least in a healthy subject) its previous con- 

 dition; and it is probable that the portion of its mucous membrane which had 

 been thrown off as Decidua, is very early reproduced. 



987. As to the reason why the period of Parturition should be just nine 

 months after the occurrence of Conception, we know nothing more than we do 

 of that of similar periodical phenomena in the history of the life of Man and 

 of other living beings ; all of which must be considered as occasional manifesta- 

 tions of changes that are constantly in progress, whose rate, being dependent 

 upon the degree of Heat supplied, is so uniform in warm-blooded animals as to 

 secure a very close conformity to a common standard. 3 There is evidence that 



1 In addition to the evidence already cited, of the rapid occurrence of fatty degenera- 

 tion of the uterine structure after parturition, the Author may mention that he has been 

 informed by Dr. Retzius (Professor of Midwifery at Stockholm) that he has detected a 

 large number of fat globules in the urine of puerperal women. Is it not possible, it may 

 be further asked, that some of the oleaginous matter so copiously poured forth by the 

 mammary glands, may be derived from this source ? Such an economy of nutrient mate- 

 rial would be consistent with what we elsewhere meet with ; and the idea is conformable 

 to the faet, that the proportion of butyrine in the milk is much greater in the earlier, 

 than in the later months of lactation. 



2 This may be best illustrated by the analogy of a Ley den jar which is being charged 

 by the continuous action of an Electrical Machine, and which is so arranged as to c/wcharge 



