878 KEPRODUCTION, DEVELOPMENT, GROWTH AND DEATH [CH. LIX. 



The meaning of the polar bodies has been the subject of much speculation ; it 

 is supposed that the female cell casts out certain constituents in order to make 

 room for the addition to it of material from another individual, namely, the male. 

 Some animals multiply without the intervention of the male sex, or the intervention 

 occurs at long intervals with many intermediate generations ; this is known as 

 parthenogenesis. One must therefore suppose that the female cell has within it a 

 male component which can be transmitted to future generations. The ovum of 

 these animals only extrudes one polar globule. It may therefore be that the 

 second polar body contains the hereditary male element which is retained in 

 parthenogenesis, but in animals which multiply sexually this is got rid of prior 

 to the inception of the new male element. 



This brings us to the stage in our story when both male and 

 female elements are ripe and ready for union. Logically we should 

 next study how the union is accomplished. But first we must step 

 into a bye-path, and before leaving the ovary and testis enquire 

 whether these organs have any other functions than those we have 

 already discussed. This may best be done under the following new 

 heading. 



INTERNAL SECRETIONS OF OVARY AND TESTIS 



The operation of castration, that is, the removal of the essential 

 generative organs, naturally leads to a loss of reproductive power, 

 but it has other effects of a more general kind on the organism, 

 which mainly influence what are known as the secondary sexual 

 characters. This effect is believed to be due to the lack of certain 

 internal secretions formed by testis and ovary respectively. 



Testis. Some years ago Brown-Sequard, then an old man of 

 seventy-two, stated that the subcutaneous injection of testicular 

 extracts into himself produced marked rejuvenating effects. More 

 recently Poehl has described the beneficial stimulating effects of a 

 substance prepared from the testis, which he terms spermine. He 

 has assigned to it the formula C 5 H 14 N 2 , but Dixon has shown that 

 it is a mixture of proteins with other organic and inorganic materials. 

 The supposed tonic effects of such injections are regarded with 

 great suspicion, and temporary benefit, if it does occur, is mainly 

 attributable to suggestion. 



The principal evidence upon which the assumption rests that the 

 testis forms an internal secretion, is derived from the effects of 

 castration, or from cases in which the testes do not descend into the 

 scrotum. If the operation of castration is performed before puberty, 

 the reproductive apparatus which is left (vesiculse seminales and 

 prostate, but not the penis) atrophy ; the secondary sexual characters 

 (growth of hair on the face, deepening of the voice, etc.) do not 

 develop ; the body remains infantile, but never assumes female 

 characters. The body, however, grows, and in some cases there is 

 overgrowth of the skeletal and adipose tissues. 



In animals there is corroborative evidence of the same nature. 



