PHASES IN THE LIFE OF THE INDIVIDUAL 713 



remain within the body cavity, it is at puberty that these organs first 

 descend into the scrotal sacs. The puberty acceleration in growth 

 which takes place in man has been already referred to. This change 

 is accompanied, as is well known, by alterations in the general 

 proportions, associated with an increase of strength, a deepening of 

 the voice, and a growth of hair on the face and other parts of the 

 body, processes which are not completed until about the twenty-fifth 

 year.i In temperate climates puberty begins in boys at about the 

 fourteenth or fifteenth year ; in tropical countries it is usually a few 

 years earlier.^ It is at this period that ripe spermatozoa first make 

 their appearance in the seminal fluid, which is henceforward secreted 

 in considerable quantity. 



In women puberty occurs at a slightly earlier age than in the 

 male sex. The constitutional changes characterising this period take 

 place more suddenly in the female, the girl almost at once becoming 

 a woman, whereas the boy is several years before he develops into a 

 man, complete maturity not being reached until the twenty-fifth year. 

 Moreover, the onset of puberty in the girl is marked more precisely by 

 the coming of menstruation, which may make its appearance in temper- 

 ate climates in the thirteenth year. At about the same time the pelvis 

 widens, and the other characteristic anatomical changes take place ; 

 the subcutaneous layer of fat, the development of which assists so 

 largely in giving the body its graceful contour, is deposited; while 

 the internal generative organs enlarge and ripe ova are produced by 

 the ovary .^ 



1 The breaking of the voice occurs to a certain extent also in girls but less 

 sudden. Appended is Earth's table of the length of the vocal cords at different 

 ages (as quoted from Feldman, Ante-natal and- Post-natal Child Physiology, 

 London, 1920). 



Age in years 



Males, mm. 

 Females, mm. 



It is thus seen that the lengthening of the cords even in boys is not 

 absolutely sudden but extends over years. 



2 Havelock Ellis, Man and Woman, 5th Edition, London, 1914. This book 

 contains a wealth of information concerning growth, etc., and many other 

 matters. Steinach and Kammerer, "Klimak und Mannbarkeit," Arch. f. 

 Entioick.-Meeh., vol. xlvii., 1921. 



' ^ Runge" (E.), however (" Beitrag zur Anatomie der Ovarien Neugeborener 

 und Kinder von der Pubertat^eit," Arch. f. GyndL, vol. Ixxx., 1906), states 

 that growing follicles are by no means uncommon in ovaries of young children. 

 In the first year of life he found follicles of considerable size, and in the second 

 year still larger ones, some having a diameter of 135 m. In the third year 

 degenerate follicles were also found. During this and the following years there 

 was a progressive increase in the size of certain of the follicles until the ovaries 

 became scarcely distinguishable from those of adults excepting for their smaller 



23 A 



