060 OF GENERATION. 



manufacturing towns than in thinly peopled agricultural districts. The 

 mental and bodily habits of the individual have also considerable influence 

 upon the time of its occurrence ; girls brought up in the midst of luxury or 

 sensual indulgence undergoing this change earlier than those reared in hardi- 

 hood and self-denial. The changes in which puberty consists are for the most 

 part connected with the reproductive system. The external and internal organs 

 of generation undergo a considerable increase of size; the mammary glands 

 enlarge; and a deposition of fat takes place in the mammae and on the pubes, 

 as well as over the whole surface of the body, giving to the person that round- 

 ness and fulness, which are so attractive to the opposite sex at the period of 

 commencing womanhood. The first appearance of the Catamenia usually occurs 

 whilst these changes are in progress, and is a decided indication of the arrival of 

 the period of puberty; but it is not unfrequently delayed much longer; and its 

 absence is by no means to be regarded as a proof of the want of aptitude for 

 procreation, since many women have borne large families, without having ever 

 menstruated. The Catamenial discharge, as it issues from the uterus, appears 

 to be nearly or quite identical with ordinary blood; but in its passage through 

 the vagina, it becomes mixed with the acid mucus exuded from its walls, which 

 usually deprives it of the power of coagulating. If the discharge should be 

 profuse, however, a portion of its fibrin remains unaffected, and clots are formed. 

 In cases in which, by the death of women at this period, an opportunity has 

 been afforded for the examination of the lining membrane of the uterus during 

 menstruation, it is found to be unusually turgid with blood, the veins in par- 

 ticular being much distended, and opening upon the internal surface by capillary 

 orifices, to which valvules are occasionally found attached. 1 Hence it is scarcely 

 correct to designate the menstrual flux as a " secretion;" although there is reason 

 to think that it may carry off, besides blood, certain matters which would be 

 appropriate to the formation of a decidual membrane, but which, if not so em- 

 ployed, become excrementitious. The interval which usually elapses between 

 the successive appearances of the discharge is about four weeks; and the dura- 

 tion of the flow is from three to six days. There is great variety, however, in 

 this respect among the inhabitants in different climates, and among individuals ; 

 in general, the appearance is more frequent, and the duration of the flow greater, 

 among the residents in warm countries, and among individuals of luxurious 

 habits and relaxed frame, than among the inhabitants of colder climes, or among 

 individuals inured to bodily exertion. The first appearance of the discharge is 

 usually preceded and accompanied by considerable general disturbance of the 

 system ; especially pain in the loins and a sense of fatigue in the lower extremi- 

 ties; and its periodical return is usually attended with the same symptoms, 

 which are more or less severe in different individuals. 



966. Much discussion has taken place respecting the causes and purposes of 

 the Menstrual flow; and recent inquiries have thrown much light upon them. 

 The state of the female generative system, during its continuance, appears to 

 be analogous to the heat of the lower animals, many of which have a sero-san- 

 guinolent discharge at that period. There is good reason to believe that in the 



and on Practical Midwifery," 1851), it would seem that the natural period of puberty in 

 temperate climates occurs in a much more extended range of ages, and is much more equally 

 distributed through that range, than others have alleged ; and that in other countries the 

 supposed parallel between plants and fruits does not hold good. The fact seems to be 

 that this, like other periodic phenomena of warm-blooded animals, is but little influenced 

 by external temperature, simply because the rate of growth and development, of which 

 these phenomena are the exponents, is determined by the temperature of the body itself, 

 not by that of the surrounding medium. Still it is quite possible that external warmth 

 may have a slight influence in determining early puberty ; since, as already shown, it 

 tends to maintain a somewhat higher degree of bodily heat ($ 651). 

 1 See Whitehead "On Abortion and Sterility," pp. 1337. 



