120 THE PHYSIOLOGY OF REPRODUCTION 



cells have a connective tissue origin, but these investigators do not 

 appear to have traced the successive stages of cellular development 

 with the same completeness as Miss Lane-Claypon. 1 Sainmont is of 

 opinion that they have a trophic function, a suggestion which was 

 first made by PHii-. 



Tin -re would seein to be no doubt that the developing ova in the 

 immature ovary subsist and grow at the expense of the surrounding 

 tissue. Thus protoplasmic masses, formed by the aggregation of 

 very young ova, have been described by P>alfour, 3 who made the 

 suggestion that one ovum may develop at the cost of the others. 

 These aggregations of ova were noticed in the ovary of the fostal 

 rabbit at about the sixteenth day of pregnancy. A day or two 

 previously the ova were observed to be separate. Miss Lane-Claypon, 

 who confirms the observation, is of opinion that Balfour's suggestion 

 was right, and that the ova which disappear serve ultimately as 

 food-stuff for the one ovum whose condition happens to be the most 

 vigorous. " This cannibalism on the part of the young ovum is not 

 surprising, if the life of an ovum be considered. It is really but the 

 normal condition of the cell at all its stages of development ; it grows 

 and fattens at the, expense of other cells. In the young ovary, it is 

 starting its first stage of growth and must devour other cells ; later 

 on, during the -rowth of the follicle, it lives upon the follicle-cells, 

 and later still, when, after fertilisation, the [term] ovum in its 

 extended sense refers to the young fo-tus, [this latter] lives on the 

 material provided by the cells of the maternal organism." 4 



MAT! liATloN AM 0\| l.ATION 



The youngest and smallest Graafian follicles lie near the surface 

 of the ovary, but pass inwards as they increase in size. The large, 

 mature follicles, however, come to lie just below the surface from 

 which they begin to protrude visibly at the approach of the breeding 

 season. I hiring the pr>o-strum one or more follicles (the number 

 varying in different animals, according to the si/e of the litter) may 



to I'opotl' (.1 /-//. </> Hint., vol. xxvi., litll) tin- origin of the 

 interstitial cell-, may vary with the sjH-oit-s ''mole, stoat, (log). For description 

 of interstitial eella in tic- ^uiin-a-pi^ see Atkins (.\iit. .!:.. vol. \.\\i.x., 1!H1), 

 and in man * Wol/. .lr</-. /'. '//////>'/., vol. xcvii., l!tl:2), and see ahovc. p. 114. 

 St-c al-o Srliaetlei (. I /<//./. flit link., vol. xciv., I'.tll). 



'-' I'M ii^er, /'/, ,//, A'/.vsA,. , <./'////</ ,/, /,/,-.< 



Jolll, I'"'. 



1 I-iiif-t'las -poii. "On ( voi/en-sis. etc.," !<. <'<(. That one ovum may de- 

 velop ;tt the expense ,,f others i< particularly well shown in ll;i<lra, Tnlnl<ir'i, 

 and certain other ( 'o-l.-m.-iat.-^. 'I'h,. nuclei of the ingested ,,va continue to 

 be easily recognisable even during the early -cementation stages of the 

 developing egg. 



