A Historical Summary of the previous records of the pluriovular
follicle is given,and it is pointed out that analysis reveals
the lack of standardisation of these,and the consequent uncertainty
of the actual frequency of the condition.
Various systematic examinations of 496 adult ferret ovaries
have been made. The numerical results are set forth. Two separate groups of the ovaries were chosen at random,and sections were
examined. In both groups,about one third of the ovaries showed the
pluriovular condition.
The proportion of pluriovular follicles to the total number
of follicles examined in a fairly large series was,very roughly,
0.1 per cent. When the smallest follicles were excluded,and the
sections were examined serially,the percentage was about 1.5.
100 pluriovular follicles have been specially investigated,and
the results are introduced into the discussion.
The growth and destiny of the pluriovular follicle are discussed.
Conversion of true pluriovular follicles to uniovular is held to
be rare. Degeneration of the ova and variations in the extent of
growth of the various ova in a follicle are illustrated.
The species-distribution of the follicle is indicated,as far as
possible. The opossum and the dog are noted as frequently exhibiting
it. In Dasyurus,in the Texas armadillo, in man? and in at least certain varieties of pig, the condition appears rare.
(1) Plurinucleated ova. The ferret negatives the suggestion that
there is a relationship to the pluriovular follicle.
(2) Abundance of small follicles. No evidence is obtained from
the ferret.
(3) Tubular ingrowths of the germinal epithelium - notable in the
dog;rare in the ferret.
The relationship of connective tissue to follicular cells is
treated.
(i) The possibility of secondary failure of the separating connective
tissue at various stages of follicular development id discussed,
and dismissed as improbable in the ferret ovary
(2) The factors involved in the primary failure of the connective
tissue to separate primordial follicles,are suggested. The pluriovular
follicle in the ferret is attributed to this lack of balance
between follicular and connective tissues.
The degree of the abnormality is considered. Biovular follicles
were found to be the most common. The greatest deviation from the
normal in this series was a small follicle with probably 14 ova.
The relationship of ova to epithelium in the pluriovular follicle
is seen in many instances to lend support to the view of Foulis
and Van Beneden,that the zona pellucida is formed by the ovum itself.
Pluriovular follicles are found more abundantly in the non-mature ferret in the mature. 39 young ferret ovartes have been
examined for this purpose. The factors producing the condition are
the same,qualitatively,as in the adult.
The growth and destiny of the pluriovular follicle are discussed.
Conversion of true pluriovular follicles to uniovular is held to
be rare. Degeneration of the ova and variations in the extent of
growth of the various ova in a follicle are illustrated.
The relationship of the condition to fertility, in particular
to "fecundity" (Pearl) is treated. Direct influer ce,by rupture
of ari abnorma. 1 follicle,is cmnsidered rare. Two instances of rupture are recorded,in the ferret. Indirect relationship is dissussed
in the light of possible types of evidence:
(1.) Abundance of small follicles - doùbtful evidence of fecundity.
(2.) Ovulation -rate (and litter- size). Pluriovular follicles may
abundantly
occur along with great fecundity(opossum);but they may occur\rrith -eat
out great fecundity (dog)ami-laft43. Fecundity may be great and the
follicular abnormality not common (Dasyurus and pig). In the
ferret,fecundity is moderately high,and the follicular abnormality
is not very frequent. The evidence fromsiñdividual instances is
inadequate. The ferrpt ovaries which most abundant pluriovular
follicles do not show a high ovulation -rate.
