1012 OF GENERATION. 



sufficient to determine important modifications in the developmental processes 

 of the Embryo, to which her blood furnishes the materials, can scarcely admit 

 of a question, when we recollect what an influence the presence or absence of 

 particular substances has in modifying the growth of parts in the adult ( 203). 

 The error of the vulgar notion on this subject, lies in supposing that a sudden 

 fright, speedily forgotten, can exert such a continual influence on the nutrition 

 of the Embryo, as to occasion any personal peculiarity. 1 The view here stated 

 is one which ought to have great weight,' in making manifest the importance of 

 careful management of the health of the Mother, both corporeal and mental, 

 during the period of pregnancy ; since the constitution of the offspring so much 

 depends upon the impressions then made upon its most impressible structure. 



1015. It is frequently of great importance, both to the Practitioner and to 

 the Medical Jurist, to be able to determine the age of a Foetus, from the phy- 

 sical characters which it presents; and the following table has been framed by 

 Devergie 2 in order to facilitate such determination. It is to be remarked, 

 however, that the absolute length and weight of the Embryo are much less safe 

 criteria, than its degree of development, as indicated by the relative evolution of 

 the several parts which make their appearance successively. Thus it is very 

 possible for one child, born at the full time, to weigh less than another born at 

 eight or even at seven months; its length, too, may be no greater: but the posi- 

 tion of the middle point of the body will usually afford sufficient ground for the 

 determination; since, during the two latter months of pregnancy, the increas- 

 ing development of the lower extremities brings it lower down. 



Embryo 3 to 4 weeks. It has the form of a serpent; its length from 3 to 5 lines; its 

 head indicated by a swelling ; its caudal extremity (in which is seen a white line, indicat- 

 ing the continuation of the medulla spinalis), slender, and terminating in the umbilical 

 cord ; the mouth indicated by a cleft, the eyes by two black points ; the members begin 

 to appear as nipple-like protuberances ; the liver occupies the whole abdomen ; the blad- 

 der is very large. The chorion is villous, but its villosities are still diffused over the 

 whole surface. 



Embryo of 6 weeks. Its length from 7 to 10 lines; its weight from 40 to 75 grains; 

 face distinct from cranium ; aperture of nose, mouth, eyes, and ears perceptible ; head 

 distinct from thorax ; hands and forearms in the middle of the length, fingers distinct ; 

 legs and feet situated near the anus ; clavicle and maxillary bone present a point of ossi- 

 fication ; distinct umbilicus for attachment of cord, which at that time consists of the 

 omphalo-meseraic vessels, of a portion of the urachus, of a part of the intestinal tube, 

 and of filaments which represent the umbilical vessels. The placenta begins to be form- 

 ed ; the chorion still separated from the amnion ; the umbilical vesicle very large. 



Embryo of 2 months. Length from 16 to 19 lines; weight from 150 to 300 grains; 

 elbows and arms detached from the trunk ; heels and knees also isolated ; rudiments of 

 the nose and of the lips ; palpebral circle beginning to show itself ; clitoris or penis appa- 

 rent ; anus marked by a dark spot ; rudiments of lungs, spleen, and suprarenal capsules ; 

 caecum placed behind the umbilicus ; digestive canal withdrawn into the abdomen ; ura- 

 chus visible ; osseous points in the frontal bone and in the ribs. Chorion commencing to 

 touch the amnion at the point opposite the insertion of the placenta; placenta begins to 

 assume its regular form ; umbilical vessels commence twisting. 



Embryo of 3 months. Length from 2 to 2g- inches; weight from 1 oz. to 1J oz. (Troy) ; 

 head voluminous ; eyelids in contact by their free margin ; membrana pupillaris visible ; 

 mouth closed ; fingers completely separated ; inferior extremities of greater length than 



' For some valuable observations on this subject, see Montgomery " On the Signs of 

 Pregnancy." Numerous cases have been recorded, during the last few years (especially 

 in the " Lancet" and " Provincial Medical Journal"), in which malformations in the Infant 

 appeared distinctly traceable to strong impressions made on the mind of the Mother some 

 months previously to parturition ; these impressions having been persistent during the 

 remaining period of pregnancy, and giving rise to a full expectation on the part of the 

 Mother that the child would be affected in the particular manner which actually occurred. 



2 " Medecine Legale," 3ieme edit. torn. i. p. 279. 



