622 OF REPRODUCTION. 



Embryo of 3 months. Length from 2 to 2| inches; weight from 1 oz. to 1 oz. 

 (Troy) ; head voluminous; eyelids in contact by their free margin; membrana pupil- 

 laris visible; mouth closed; fingers completely separated; inferior extremities of 

 greater length than rudimentary tail; clitoris and penis very long; thymus as well as 

 supra-renal capsules present; coecum placed below the umbilicus; cerebrum 5 lines, 

 cerebellum 4 lines, medulla oblongata 1 line, and medulla spinalis of a line, in dia- 

 meter; two ventricles of heart distinct. The decidua reflexa and decidua uterina in 

 contact; funis contains umbilical vessels and a little of the gelatin of Warthon ; 

 placenta completely isolated; umbilical vesicle, allantois, and omphalo-mesenteric 

 vessels have disappeared. 



Foetus of 4 months. Length 5 to 6 inches ; weight 2^ to 3 oz. ; skin rosy, tolerably 

 dense; mouth very large and open; membrana pupillaris very evident; nails begin to 

 appear; genital organs and sex distinct; coscum placed near the right kidney; gall- 

 bladder appearing; meconium in duodenum; ccecal valve visible; umbilicus placed 

 near pubis; ossicula auditoria ossified; points of ossification in superior part of 

 sacrum ; membrane forming at a point of insertion of placenta on uterus ; complete 

 contact of chorion with amnion. 



Foetus of 5 months. Length 6 to 7 inches; weight 5 to 7 oz. ; volume of head still 

 comparatively great; nails very distinct; hair beginning to appear; skin without 

 sebaceous covering; white substance in cerebellum; heart and kidneys very volumi- 

 nous; coecum situated at inferior part of right kidney ; gall-bladder distinct; germs 

 of permanent teeth appear; points of ossification in pubis and calcaneum; meconium 

 has a yellowish-green tint, and occupies commencement of large intestine. 



Foetus of 6 months. Length 9 to 10 inches; weight 1 lb.; skin presents some ap- 

 pearance of fibrous structure; eyelids still agglutinated, and membrana pupillaris 

 remains; sacculi begin to appear in colon; funis inserted a little above pubis; face 

 of a purplish red ; hair white or silvery; sebaceous covering begins to present itself; 

 meconium in large intestine ; liver of dark red; gall-bladder contains serous fluid 

 destitute of bitterness ; testes near kidneys ; points of ossification in four divisions of 

 sternum; middle point at lower end of sternum. 



Foetus of 7 months. Length 13 to 15 inches; weight 3 to 4 Ibs. ; skin of rosy hue, 

 thick, and fibrous; sebaceous covering begins to appear; nails do not yet reach ex- 

 tremities of fingers; eyelids no longer adherent; membrana pupillaris disappearing; 

 a point of ossification in the astragalus ; meconium occupies nearly the whole of large 

 intestine; valvula? conniventes beginning to appear; co?cum placed in right iliac 

 fossa; left lobe of liver almost as large as right; gall-bladder contains bile; brain 

 possesses more consistency; testicles more distant from kidneys; middle point at a 

 little below end of sternum. 



Foetus of 8 months. Length 14 to 16 inches; weight 4 or 5 Ibs. ; skin covered with 

 well-marked sebaceous envelop; nails reach extremities of fingers ; membrana pupil- 

 laris becomes invisible during this month; a point of ossification in last vertebra of 

 sacrum; cartilage of inferior extremity of femur presents no centre of ossification; 

 brain has some indications of convolutions; testicles descend into internal ring; 

 middle point nearer the umbilicus than the sternum. 



Foetus of 9 months, the full term. Length from 17 to 21 inches; weight from 5 to 9 

 Ibs., the average probably about 6| Ibs. ; head covered with hair in greater or less quan- 



ty, of from 9 to 12 lines in length; skin covered with sebaceous matter, especially at 

 nds of joints ; membrana pupillaris no longer exists; external auditory meatus still 

 cartilaginous ; four portions of occipital bone remain distinct; os hyoides not yet ossi- 

 fied ; point of ossification in the centre of cartilage at lower extremity of femur ; white 

 and gray substances of brain become distinct; liver descends to umbilicus; testes 

 have passed inguinal ring, and are frequently found in scrotum; meconium at termi- 

 nation of large intestine; middle point of body at umbilicus, or a little below it. 



770. Even at Birth, there is a manifest difference in the physical conditions 

 of Infants of different sexes ; for in the average of a large number, there is a 

 decided preponderance on the sides of the Males, both as to the Length and 

 the Weight of the body. The Length of the body in fifty new-born infants of 

 each sex, as ascertained by Quetelet,* was as follows : 



* Sur L'Homme, torn. ii. p. 8. 



