898 OF GENERATION ACTION OP THE FEMALE. 



luteum rapidly diminishes ; though its characteristic structure is still to be 

 distinguished for many months, by close inspection. 1 



746. The foregoing differences (whose ordinary existence may be consid- 

 ered as well established, although it may not be affirmed that they present 

 themselves characteristically in each individual case) are probably to be 

 attributed to the increased determination of blood which takes place to the 

 whole Generative apparatus, when it is in a state of exalted functional activ- 

 ity. It is a question, however, of much scientific interest, and one that occa- 

 sionally becomes of importance in Juridical investigations, what degree of 

 resemblance may exist between the corpus luteum which is formed after the 

 mere extrusion of an ovule, and that which has been modified by the super- 

 vention of pregnancy. For it is unquestionable that an unusual develop- 

 ment of the fibro-cellular substance may sometimes occur without impreg- 

 nation ; whilst, on the other hand, the changes which usually follow impreg- 

 nation may take place so much less characteristically than usual, that the 

 corpus luteum, even at the middle period of pregnancy, may be no larger 

 than that which is often found \vhere pregnancy has not occurred. These 

 variations, which seem mainly to depend upon differences in the degree of 

 vascular excitement of the ovaries accompanying and succeeding the extru- 

 sion of ova, render it impossible to draw any definite line of demarcation, by 

 which we may at once determine what are, and what are not, the results of 

 conception ; but the following practical rules, deduced from a consideration 

 of all the circumstances yet known, may be laid down for the guidance of 

 those who find it desirable to have some standard of judgment : " 1. A Cor- 

 pus Luteum, in its earliest stage (that is, a large vesicle filled with coagu- 

 lated blood, having a ruptured orifice, and a thin layer of yellow matter in 

 its walls), affords no proof of impregnation having taken place. 2. From 

 the presence of a Corpus Luteum, the opening of which is closed, and the 

 cavity reduced or obliterated, only a stellate cicatrix remaining, also no 

 conclusion as to pregnancy having existed, or fecundation having occurred 

 can be drawn, if the Corpus Luteum be of small size, not containing as 

 much yellow substance as would form a mass the size of a small pea. 3. 

 A similar Corpus Luteum of larger size than a common pea, would be strong 

 presumptive evidence, not only of impregnation having taken place, but of 

 pregnancy having existed during several weeks at least ; and the evidence 

 would approximate more and more to complete proof, in proportion as the 

 size of the corpus luteum was greater." 2 



747. Since the discharge of natural Ova from the ovaries takes place as 

 independently of sexual intercourse in the Human female (and in the Mam- 

 malia generally) as it does in those animals whose ova are fertilized out of 

 the body, it seems unnecessary that the seminal fluid should reach the 

 ovarium in order to effect the fertilization of the ova, since this end may be 

 answered by the contact of the two in the Fallopian tubes, or even in the 

 Uterus itself. From the experiments of Bischoff, however, it appears that 

 in rabbits, bitches, and probably in most other Mammalia, sexual union 

 usually takes place previously to the escape of the ova from the ovary, and 

 that sufficient time often elapses for the seminal fluid to reach the ovary be- 

 fore their extrusion occurs : in such cases, therefore, it would seem probable 



1 See especially the Prize Essay of Dr. J. C. Dalton, On the Corpus Luteum <>!' 

 M cn.-t.niiit.ion and Pregnancy, in the Tnmsact. of tint American Medical Association 

 tor 1M")1, and separately reprinted, Philadelphia, 1851; and the excellent section on 

 Hi-production, in his Human Physiology, Philadelphia, 1864; also, the essay of M. 

 His in Schuli/cc's Archiv, Bd. i, p. 181, in which references to the principal works on 

 the subject will he found. 



' 2 See Dr. Baly's Supplement to MUllcr's Physiology, p. 57. 



