AN
INAUGURAL DISSERTATION
ON THE
FUNCTION
OF
MENSTRUATION.
SUBMITTED TO THE EXAMINATION OF
THE REV. JOHN EWING, S. T. P. PROVOST,
THE
TRUSTEES AND MEDICAL PROFESSORS
OF THE
UNIVERSITY OF PENNSYLVANIA,
ON THE 21ST DAY OF MAY, 1795,
FOR THE DEGREE OF   
DOCTOR OF MEDICINE.
BY CHARLES EVERETT, OF VIRGINIA,
MEMBER OF THE PHILADELPHIA MEDICAL SOCIETY.
Quod, vero CAUSSAS periodicæ hujus et perennis hæmor-
rhagiæ attinet, tantis earum indago adhuc premitur diffi-
cultatibus, ut et heic non nisi probabilia sequi, nec ultra
id quam quod verisimile occurrerit, progredi liceat.
Blumenbach, Institutiones Physiologicæ,
Sect. xlii. de Menstruis.
PHILADELPHIA:
PRINTED BY S. H. SMITH, NO. 118, CHESNUT STREET.



TO GEORGE GILMER, M. D.
OF ALBEMARLE, VIRGINIA.
SIR,
Did I suppose, that in America, names
could stamp a value upon a work, inde-
pendent of what the author was entitled
to, or the intrinsic worth of his pro-
duction might safely claim, I could have
prefixed few, with greater expectations,
than yours; and I may add none, for
which I have a higher respect, or would
be more cautious in using, in all cases
of this kind, where the merit of the per-
formance must at least be doubtful. But
as the fashion of borrowing eclat from
the reputation of others, like the reve-
rence once paid to crowns and mitres,
is departing with the prejudice and ig-
norance which engendered it, I feel no
hesitation in offering you the first fruits
of that study which originated under



(iv)
your care, and has thus favoured me
with an opportunity of publicly acknow-
ledging my thanks, as well as the grate-
ful remembrance I entertain of the re-
peated attentions received from your
family. In dedicating the following
sheets to you, permit me to call it a
DEDICATION OF GRATITUDE—The wish
of a Pupil to testify his regard for a Pre-
ceptor, whom he has every reason to
respect and admire, and from whose
approbation and instruction he has al-
ways derived both pleasure and informa-
tion.
Whatever share, Sir, of medical in-
formation I may possess, or advantage I
may derive therefrom, the source from
whence they sprung, cannot escape my
recollection; nor shall I fail to accom-
pany your progress through life with
my best wishes for your health, prosperi-
ty, and future happiness.
CHARLES EVERETT. 

INTRODUCTION.
THE established rules of this University
demand of the candidate for medical honours,
some specimen of his talents or industry—In
obedience to these, I submit to the examina-
tion of the medical professors an Inaugural
Dissertation.
For the imperfections of this dissertation, I
claim the indulgence of the medical faculty,
and of the public.—An infirm state of health,
and want of time, have prevented me from
devoting to the subject that labour and atten-
tion which it well deserved.
The subject I have chosen for investigation
is that of the menses, or periodical discharge
of blood from the uterus of the human fe-
male.
This is one of the most curious and inter-
esting subjects in the great science of Physio-
logy; it has employed the pens of some of
the most celebrated philosophers and physi- 


(vi)
cians, both of ancient and modern times—
It still continues to solicit the attention of
writers, and it never can become uninterest-
ing in countries enlightened by science.
In this dissertation, I shall confine myself
principally to an examination of what I deem
to be the most probable theory of menstrua-
tion, slightly touching on its peculiarity and
design in the human female; I shall also ad-
vert to the causes of its continuation, and
healthy termination, without offering any
observations on the anomalous appearances,
or morbid inclinations, of this curious func-
tion. 



ON
MENSTRUATION.
THE function of menstruation is thought
to be peculiar to the human species. This
opinion, however, ought not to be received
but with caution, until the progress of sci-
ence has shed more light than has hitherto
been thrown on the subject.—The Physiology
of Animals is still in its infant state, nor has
their structure or their functions been ex-
amined with sufficient attention—It there-
fore becomes us to suspend a decision on this
question as yet imperfectly examined—In the
mean while, I shall take notice of some of
the facts which have been related by philoso-
phers and travellers, to prove that other ani-
mals besides the human female, are subject
to a periodical discharge of blood from their
uterus, or vagina. 

(8)
Aristotle has asserted that all the warm-
blooded quadrupeds have, at stated periods,
a discharge of blood from their genitals—The
Greek philosopher, however, allows that
these animals menstruate more sparingly than
the female of the human kind.
Some of the ancient as well as modern,
writers, have asserted that the following ani-
mals menstruate, viz. The Ape, the Cow,
the Deer, the Mare, the Whale; and even
the Skate, the Mullet, and the Tench.—
The celebrated naturalist M. de Buffon, has
particularly mentioned some of the simiæ, or
apes, as being subject to the law of menstru-
ation *.
Of late, Dr. Sparrman pretends to have
discovered, that a little quadruped (the Ca-
via Capensis of the late Naturalists) inhabit-
ing the Cape of Good Hope, is subject to this
periodical discharge of blood †.
The ingenious Professor Blumenbach ‡ in-
forms us, that he has kept several species of
female apes for several years, and that he has
* Histoire Naturelle.
† Voyage to the Cape of Good Hope.
‡ Institutiones Physiologicæ, Sect. xlii. de menstruis. 


(9)
found that they were entirely destitute of any
regular or periodical uterine discharge of this
kind.
Upon the whole, I am of opinion, that it
still remains to be proved, whether a peri-
odical uterine discharge of blood is or is not
peculiar to the human female. If other ani-
mals are really subject to this function, I
think we are to look for it in the mammalia,
or viviparous animals, that are furnished
with mammæ or teats, and which are com-
prehended under the generic name of simiæ.
—As to the opinions of Helwig, and some
other writers, that even some species of fishes
menstruate, I cannot think it worthy of a se-
rious attention.
Whether menstruation is or is not a lex
generis humani, or law of the human apecies
or kind, exclusively appertaining to it, there
seems to be good reason for asserting, that the
females of all nations, and all climes, are
subject to this periodical discharge.
It is true, indeed, that some writers * have
amused us with stories concerning whole na-
* Among others, Tonti, Lafiteau, and Johnston.
B 

(10)
tions of women who never menstruate; both
in the cold and warm climates of the globe.
But that philosophy, which examines nature
with caution and judgment, has demonstrated,
that these stories are destitute of foundation.
Menstruation, then, may be considered as
one of the essential characteristics of the hu-
man kind.—It is not, however, absolutely
necessary to the existence of the individual;
for authors have recorded not a few instances
of women, who have lived a long life without
having ever menstruated.—I do not, however,
intend to devote my attention to the consi-
deration of those singular cases—they doubt-
less depend on different and peculiar causes,
with all of which we are, perhaps, not ac-
quainted. The celebrated Morgagni, how-
ever, has shewn that in some cases of this
kind, the uterus, which is the fountain of
the menstrual flux, has been entirely want-
ing *.
I have neither time nor inclination to take
a view, and to examine the respective merits
* De causis et sedibus morborum. 

(11)
and demerits, of all the the theories that have
been published to the world, to account for
this curious function of the human female—
it will be sufficient barely to hint at some of
them, as we pass over their enumeration.
All the theories on this subject may be re-
duced to four or five, viz. The influence of
the moon—an internal fermentation—plethora
both partial and general—and the impressive
influence of venereal desires—The first as
being contradicted by the experience of every
individual, and the second as being incompa-
tible with the health or circulation of the
fluids, have long since ceased to be plausible.
I shall chiefly attend to the doctrines of
conformation and plethora; though not with-
out previously observing, that whatever share
the venereal orgasm (to use the language of
some medical writers) may have in the pro-
duction of menstruation, such an orgasm or
exertion does not appear to me adequate to
explain the various phenomena of the func-
tion now under consideration. Physiology
teaches us, that the exility and sensibility of
the organs of the body are necessary to the 

(12)
operation of every stimulus—In some in-
stances we find those of the uterine system
greatly impaired or diseased; nay, sometimes
their powers appear almost destroyed, as in
Paraphlegia, &c. and yet the uterine dis-
charges suffer very little derangement:—We
also find those discharges return, after long
cessations, when the passions are obedient to
old age, and when the strength of venereal
impressions has vanished from the torpid sys-
tem—On the contrary, we sometimes observe
the cessation of the menses long before the
business of generation has ceased to be attend-
ed with its peculiar pleasures; a proof, I
think, that the stimulus of lascivious ideas,
or, in other words, animal gratification, can-
not be the sole cause of the continuation, or
final termination, of this periodical discharge;
moreover, we also observe the menses in al-
most all the cases of mania; and in this de-
rangement of the intellects, no venereal im-
pulse, no energy arising from former plea-
sures, can well be supposed to take place—I
conclude, therefore, that the theory of pe-
culiar conformation united with plethora,
can receive but little injury from venereal 

(13)
orgasm.—The doctrine of Plethora, although
it possesses many advantages, is nevertheless
far from being free from all objections—The
supporters of this doctrine have divided them-
selves into two parties, which may not im-
properly be called Universalists and Partial-
ists; the former contending for the existence
of general, and the latter for that of partial,
Plethora, as the cause of menstruation.
In attending to the different appearances
of the menses, in different habits, and under
different circumstances, we for the most part
observe a plethoric state of the system preva-
lent in all or most of those periods which are
most natural to each individual.
The consequences attending an interrup-
tion of those periods, by translation and effu-
sion in some other part, together with the ef-
fects of any depleting, means, near or about
those periods, seem to give considerable
strength to the opinion—Since, then, the
doctrine of plethora seems to furnish the most
natural and the most easy explanation of most
of the phenomena of the menstrual discharge,
I can see no reason why a general plethora
B2

(14)
may not be attended with a partial congestion
or determination of blood to the uterus, and
why a topical congestion, when barred from
its usual outlets, may not be the cause of a
general fulness.
In enquiring, however, into this plethora
as the exciting cause of the menstrual dis-
charge, we shall find it liable to great modifi-
cation, from climate, from situation, and
from the various incidents of life; the first
in retarding or hurrying its eruption, the se-
cond in supporting and maintaining its regu-
larity, and the third by inducing disease,
causing various errors as to time, quantity and
duration.
By Plethora, physicians mean that state of
the system, containing a greater quantity of
fluids than is sufficient for the demands of the
body, or proper for the purposes of the ani-
malizing powers; particularly a superabun-
dance in the contents of the sanguiferous ves-
sels, in either actual increase of fluids, or
constriction of the solids conveying them:
It is this absolute increase of quantity which
appears to be present about the time when

(15)
the menses first make their appearance—But
it is not yet decided by what law or principle
of the female system this superabundant quan-
tity of fluids is at this time generated—The
prevalence of arterial plethora over that of
venous, is known to take place from infancy
to that period of life at which the increase of
the body ceases, and a kind of equilibrium is
established in all its parts—At this period our
machine stands balanced on a point of time,
which constitutes the vigour and bloom of hu-
man life. We are so constructed by nature,
that every part of the system appears to pos-
sess a strength and power proportionate to our
capacities of using them—(I speak entirely of
the healthy and well conditioned body)—It
is remarkable, that the completion of those
parts which are most essential to the present
demands of the animal, and the best adapted
to his instinctive and rational powers of using
them, first take place; whilst, on the contra-
ry, other organs that are destined for future
purposes, and of which the present state of
the system is unconscious, remain nearly in
their embryo-weakness, until the gradual
progress of animalization evolves them, and 

(16)
the natural laws of the œconomy demand
them—The organs of generation appear to
be of this kind; and indeed the peculiarity of
the sexes is never so prominently impressed
upon our observation, until those organs re-
ceive their completion, and the proper acme
of the system is established—This evolution,
then, of the general system, we observe to
take place at different times, but in regular
succession, influenced perhaps by the strength
and density of the different vessels dependent
on original conformation and stamina, regulat-
ing, as it were, the plethoric impulse—It is in
this way that we can explain why the superior
parts of the body progress faster, and how a
successive completion takes place in the rest
—It is here likewise that the combination of
plethora seems evidently active, first in pro-
ducing the bulky head in childhood, when,
from its topical influence, the Schneiderian
membrane of the nose is often ruptured, and
an Epistaxis or discharge of blood from the
nose, if not peculiar, becomes at least much
more common, to that stage of life—Second-
ly, when, by the increased bulk of those parts,
the plethoric impulse is diverted from the 

(17)
cranium to the thorax, hæmoptesis or a dis-
charge of blood from the lungs succeeds epis-
taxis, and becomes chiefly incidental to the
juvenile state of life—Thirdly, when most
other hæmorrhages have ceased, a determina-
tion to the pelvis takes place, producing the
menses in women, and the hæmorrhoids in
men; for although this last may be a morbid
evacuation, it is nevertheless hardly ever ob-
servable until about the time of puberty or
middle age, when the determination to the
pelvis is supposed to have taken place.
That a general fulness of the sanguiferous
system is actually present about the time of
menstruation, I infer from the consequences
which result from a different habit. We ob-
serve that weak and emaciated females arrive
very late, and sometimes never, at that con-
dition of the body when aptitude and appe-
tite impel them to venereal enjoyments, and
not until symptoms of plethora are evident—
Besides, without admitting the presence of
general plethora sufficient to distend the
neighbouring parts of the system, and to
overcome the resistance made by the imper-
C 


(18)
fect state of the genital organs, I cannot see
how the Partialists, as I may call them, can
procure even topical congestion, unless they
imagine it is brought about by inflammatory
stricture, which would undoubtedly defeat
the intention of the whole; and if the trans-
mission of the blood through the several parts
which were nearly complete, was as easy or
similar to that of a meagre or implethoric state
of the system; what reason have we to sup-
pose it would deviate from passages already
clear and unimpeded, to search out those in-
numerable convolutions and ramifications
which we find in the organs of generation of
both sexes?
We cannot suppose that such an effect might
slow from a superior vis impellens in those
vessels, arising from more perfect evolution;
because this power, in a certain degree, is
dependent on distention, and distention (by
which I mean healthy distention) is incon-
sistent with a scarcity of fluids in the system
of blood-vessels.—Thus I think it appears,
that without a general plethora, the organs of
generation would probably remain imperfect, 
and

(19)
and a partial congestion could scarcely exist—
and though it may sometimes seem to take
place, independent of any co-operation of
the system, yet those appearances are never
observable until after the menses have assum-
ed their natural destination, and their fre-
quent discharge have rendered those vessels
more yielding and dilatible, and of course
more ready to receive and dispose of any sur-
charge of blood, that may from time to time
happen to encumber the system. But let us
suppose, for a moment, that by some hither-
to inexplicable law in the human œconomy,
that a partial congestion should take place in
the commencement of menstruation, uncon-
neded with a general fulness of the body—
May it not also be supposed, that less resist-
ance would be found in the neighbouring a-
nastamosing branches of the Iliacs, the diame-
ters of which were already sufficiently en-
larged of previous evolution, than in the un-
distended tubes which terminate in the fun-
dus uteri? Moreover, when menstruation has
taken place in any individual, and disease,
of whatever kind, obstructs this discharge
through its natural channels, does not a transit
C2 


(20)
to other parts strengthen the conjecture, and
at the same time confirm the doctrine of uni-
versal plethora, attended with topical determi-
nation, by proportionate hæmorrhages, taking
place in the most distant parts of the animal bo-
dy? As, in cases of obstructions of this kind
have often been observed, and blood from the
eyes, the nose, the ears, the roots of the nails,
the lungs, the pores of the skin *, &c. has been
known to compensate its repulsion from its
ufual courses, and preferve that balance so es-
sential to the health of the system.—Thus,
then, when general plethora, accompanied
with its healthy impulse, presses on the un-
evolved organs of generation, leaving per-
haps no other outlets of the system so likely
to yield to its influence, the irritability of
those parts becomes awakened, thereby soli-
citing a greater afflux of fluids, which conti-
nues to accumulate in the vessels of the uterus
until, by the joint effort of plethora and dis-
tention, the long obstructed passages of twelve
or fourteen years, are at length unlocked.
* Vide Haller's Elementa Physiologiæ Corporis Hu-
man!, Tom. VII. pa. 157, 8, 9, & 160. 

(21)
I infer then, that a general plethora, co-
operating with, or rather terminating in, a
partial congestion, from whatever law in the
system it may arise, is a principal agent in
exciting the menstrual discharge. The united
efforts of this plethora and congestion conti-
nually distend the different organs of the bo-
dy, until those organs have acquired suffici-
ent strength to resist the plethoric impulse,
and to determine its plastic power to parts that
are more capable of yielding to its impetus.
A period then must arrive, when the genital
system will receive its completing influence,
and act in unison with the other powers of the
animal body, when new impressions will be
excited, and new desires will prompt to new
pleasures. Possibly there may be some con-
nection between the late evolution of those
organs and that period when reason and
judgment are more mature, and better capa-
ble of managing that gust of passions which
are incident to the irritable age of puberty.
When, therefore, the plethoric state, of
which I have been speaking, comes to be ge-
nerally resisted by the increased bulk and
power

(22)
power of parts that are more complete, it
may easily be conceived how a determination
to the vessels of generation may ensue, both
by their dependent situation, membranous
connection, and the want of that extension
which is necessary to occupy their natural li-
mits, and hold their weight in animal balance.
The consequence of this determination in
the human female, is a turgescency through-
out the whole system of the uterus; new sen-
sations, evolving new desires, are awakened,
and hurry the most impatient sensibility
through the whole region of the pelvis. The
ova, emerging from their confusion, overtop
their calices, distend and irritate the ovaria,
and impel the blood into the anastamosing
branches of the uterus. A revolution appears
to riot in the system, and to weave a texture
both of torturing and pleasing sensations.
Perhaps here the venereal orgasm may co-
operate, and, from the extreme excitability
of the parts and novelty of the stimuli, en-
cumber the mind with a chaos of delusion
and fanciful extravagance, which are fre-
quently so strikingly characteristic of the pe-
riod to which we allude. 


(23)
This orgasm may re-act, as it were, upon
the exciting cause, and increase the tumult
and disorder already present.
The vessels of the uterus become distend-
ed, their convolutions are straitened, their
extremities are exposed, and being subject to
the direct action of the impelling power, be-
gin at first to discharge the thinner parts of
their contents, the operating causes still con-
tinuing to act, and their extremities still be-
coming more enlarged, an hæmorrhagy at last
takes place.
But upon the principle of evolution, ple-
thora and extension, as they appear to have a
similar rotine in both the sexes, I may per-
haps be asked, why does not a similar evacua-
tion take place in the male? Although, at the
age of puberty, a plethoric distention may
take place in the genital organs of the male,
and this seems very probable from the analo-
gous tumescence of the mammæ, which is ob-
servable in both male and female; still this
determination may be subject to the peculiar
operation of each, and governed by the pe-
culiar organization of their different parts. 

(24)
The different ramifications of vessels, their
different terminations, and perhaps also, their
different degrees of density and firmness, con-
neded with some relative peculiarity in the
general system, may be sufficient to preclude
any hæmorrhagy of this kind in the male.
Moreover it is not altogether improbable that
the want of ovaria may diminish the quantity
of this determination in the male, whilst the
elaboration of the semen may possibly dispose
of the surplus.
May not this more sparing determination,
and the continual absorption of a fluid so
highly stimulating as the semen, assist us in
explaining the larger bulk, the larger growth,
and consequent superiority of strength, which
are generally observed in the male? And does
not this theory appear to be confirmed in the
athletic bodies and masculine features of those
women who menstruate but little?
Perhaps also the labours of parturition in-
cumbent on all females, and tending to debi-
litate, may embrace the inferiority of those
numerous species of female animals which it
is supposed do not menstruate: or perhaps
the most decisive answer to a question of this

(25)
Kind may be, that the male, from his desti-
nation, has no use for such functions, nor
could they have any relative connection with
those important consequences for which na-
ture evidently designed them in the female.
But if the menstrual evacuation be design-
ed for, or is essential to, propagation, it may
be further asked, why are not the females of
other animals subject to a similar discharge?
And why should the existence of the race of
Men alone, in all countries, depend upon a
peculiarity of this sort?
To these questions, I would in the first
place answer, by asking in my turn, why the
existence of men should depend upon the
mode that is peculiar to any other animal?
Or why has not nature formed for man, as she
has done for the frog, a stagnant lake, in
which the former, like the lattter, might,
through the medium of the water *, impreg-
nate the ova many days after their exclusion
from the uterus? Doubtless because she found
that her great intentions were much better
*See Experiments of Abbe Spallanzani.
D

(26)
answered by the mode she chose. Indeed she
seems to have decreed that some of the func-
tions of the animal œconomy should be very
differently performed in different animals:
For instance, that the brute creation should
not constantly possess the power of procrea-
tion, which seems to be given to the "human
race in consequence of the gift of reason *."
But I have already observed, in a former pan
of this Dissertation, that it is asserted by ma-
ny eminent naturalists, that the menstrual
discharge is not peculiar to the human spe-
cies. Let us suppose, however, that it is ex-
clusively confined to the human female, still
it must be allowed, that certain species of ani-
mals have a peculiar evacuation from their
uterus or vagina, as often as they are dis-
posed to venereal enjoyments. This evacu-
ation also mostly happens at that period when
plethora and distention are evident? How
far the more stimulant diet, and other habits
of our species, together with the more deli-
cate and slender conformation of our female,
may co-operate in their more copious dis-
charges, I shall not take upon me to deter-
* See Dr. Spense. 

(27)
mine. It seems evident, however, that the
uterus in the brute being almost horizontal
with respect to the body, and in the human
female approaching nearly to a perpendicular
line, the latter must admit of the operating
causes, with much more facility than that of
the former, and of course an accumulation of
blood must more frequently be the conse-
quence in the one than in the other, inde-
pendent of any animal influence.
It may be objected, that if plethora were
the prelude to the menstrual discharge, that
the loss of a few ounces of blood would not
be sufficient to remove the inconveniences of
its general operation. It may likewise be
objected, that women menstruate a short time
after parturition, when they cannot be sup-
posed to be in a plethoric state.
In answer to the first of these objections,
I would suggest the known advantages of
critical evacuations, in the miliary fever,
the inflammatory small pox, and in all con-
gestions of the head: these are evidently re-
lieved, and sometimes instantaneously cease,
by a trifling effusion of blood from the
nose.

(28)
With respect to the other objection, I
would remark, that the sanguificating princi-
ple, in all healthy animals, appears to exist
in such a manner that its powers shall be
proportioned, in a certain degree, to the ex-
traordinary demands of the system.
Women, during gestation, are accustomed
to prepare more blood than is necessary for
their own nourishment. During this period,
the vessels of the uterus become greatly dis-
tended and enlarged: the habit of nine
months, having determined a quantity of
fluids to those parts, equal to the enlarged
diameters of their vessels, and the nourish-
ment both of mother and fœtus requiring
greater exertions in this sanguificating prin-
ciple, a plethora, and a subsequent evacua-
tion, become the necessary consequences of
delivery.
This, however, will disappear, as it gradu-
ally increases, when the augmented bulk and
nourishment of the fœtus, no longer solicit it,
and the gradual collapse of the vessels begins
to restrain it. 


(29)
What may have been the intention of this
preparation of a greater quantity of blood
than is necessary for the female's own nourish-
ment, may, perhaps, admit of some specula-
tive controversy; but its ultimate design
seems to have been the nourishment of the
fœtus, and the fine qua non of propagation,
and plethora the immediate efficient cause of
the discharge *. Possibly its determination to
the uterus, may embrace other advantages;
such as, first, to indicate that condition of
the ova which is most proper for fecundation;
for about those periods, impregnation is most
apt to succeed: secondly, to keep the vessels
in a proper state for receiving and retaining
the conception, when it has issued from the
fællopian tube, and to afford it necessary food
during its detention: and, lastly, may it not
serve to facilitate the powers of absorption,
and maintain an aptitude for procreation, by
lubricating the genital tube, and washing off
all impurities? May it not also increase the
sensibility of those parts, by moistening and
relaxing their nervous terminations? Perhaps
it may also serve to keep awake those necessary
* Dr. Spense. 


(30)
sensations, which are liable to be exhausted
by that disposition in our species to gratify,
rarely to be met with in other animals; or,
as an ingenious author * has observed, for the
purposes of conception and its consequence,
there is formed in the general system a sur-
charge of blood, which is determined to the
genital organs, in the same manner as other
things are determined to other outlets.
I shall now briefly touch on some of the
apparent causes of the continuation of the
menstrual discharge.
Menstruation having once taken place, and
the blood having once found a passage to the
uterus, continues its periodical course, in
well conditioned habits, till about the age of
forty-five or fifty, at which time this function
generally ceases.
But how this periodical return and healthy
regularity are continued, has been a subject
of much speculation, and one upon which
much hypothetical reasoning has been spent.
The most probable opinion appears to me to
be peculiar conformation, and the power of
* See Speculations on Impregnation, by a Physician. 

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habit known to be so influential in the animal
system: to these I would add the continual
progress of the ova, and the pendent ter-
mination of the vessels of the uterus. Per-
haps an association of ideas and motion, as an
ingenious professor supposes *, may be also an
auxiliary agent in this business.
That habit may operate, seems evident
from the analogy of various other hæmor-
rhages, both natural and artificial, in the
human body. Thus we observe that the
practice of blood-letting in the human, as
well as in the brute, system, tends to increase
the action of those powers employed in the
formation of blood; and may, in some cases, 
even render its repetition necessary. May not
also the ovaria, even independently of uterine
vascularity and disposition, contribute some
part by the progress of their ova to maturity?
The periodical numbers appear likewise in
some measure regulated by the quantity of
blood repaired, and employed in dilating the
vessels of the uterus. And may not this
quantity in the healthy female (for we sel-
* Dr. Rush in his Lectures. 

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dom find it the same at different times) in-
dicate the state of the ova, and explain the
reason why the last menstruation, before the
female becomes impregnated, is generally
more copious than most of the former? And
the reason why many menstruations happen,
without impregnation, is perhaps owing, toge-
ther with the influence of peculiar determina-
tion, to some derangement in the feminal in-
halers, and also to that state of the ovum,
tending to the point, which admits its perfect
developement. May not incomplete men-
struation (for, as I before observed, the
quantity is seldom stationary, varying from
four to fourteen ounces) and sometimes its
total suspension for many months, without
any apparent cause, or consequent derange-
ment in the animal functions, point out a less
influential state of the ovaria, perhaps arising
from the imperfection of their ova? And does
not its return to the uterus some short time af-
ter parturition, in spight of every effort to di-
vert it (as keeping up the determination to
the breast) evidence a capacity for secunda-
tion? While its suspension for years, and
then recurring, at the same time that it explains 

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the interval which sometimes happens in fami-
ly births, may serve to shew the dependence
of this evacuation on certain states of the ova-
rian system.
Together with those causes, perhaps ele-
mentary influence may accidentally co-ope-
rate, especially when happening at those pe-
riods which may be peculiar to that state in
each individual; that the primary effect of
this influence on our atmosphere, may have
some relative operation on menstruation, I
infer from the authority and writings of Dr.
Mead *, who remarked a peculiar disposition
in the body to hæmorrhage, when the pres-
sure of the atmosphere was lightest; also upon
the credit of Dr. Kirkland †, who informs us
of a clergyman in England, who could tell
with certainty the hour of delivery (after
symptoms came on) even in the most linger-
ing cases, by his observations on the moon.
The uterus having once thrown off the dis-
tending blood, a temporary collapse or con-
* See his celebrated work, de Imperio Solis et Luræ
in Corpore Humano.
† See his Med. Surgery.
E


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traction of its vessels ensues; but in a short
time the loss is again repaired, and the vessels,
from frequent repletion, become more easily
distended; the same causes operate, and the
same effects follow; the blood is more or less
collected in the uterus; its vessels become
turgid, and at length give out a part of their
contents. But if it should be asked, why
menstruation recurs oftener than any other
periodical hæmorrhage? Should not the time
when, and the situation in which, other dis-
charges take place in the body, as epistaxis in
the nose, and hæmoptesis in the lungs, both
happening in the earlier part of life, before
the system has acquired sufficient strength to
resist; both also admitting of much less me-
chanical influence, independently of any ani-
mal exertion: should not a different conforma-
tion of parts, together with the peculiar pow-
ers of the ovaria already alluded to, be deem-
ed a satisfactory answer;—I must reply in the
language of the great Haller *, and say, I do
not suppose myself more bound to answer,
than if you were to ask me why the human
fœtus remains nine months in utero, the
* See Element. Physiol. 

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mare's eleven, and the sheep's four? Or why
in seven weeks after the blossom, the cherry
is ripe, the apple in four months, and the
chesnut in five?
We come now to that period of life when
a retrograde order appears to take place in the
system: the body decreases, and, together
with the mind, calmly approaches that autumn
which neither enjoys or feels the irritable
seasons of youth; all its organs grow more in-
sensible, and that rigidity peculiar to increas-
ing age, begins to compress or obliterate the
vessels, while plethora no longer continues to
distend them; that surplus of blood of which
we have already treated, seems gradually to
diminish, together with the capacity for sup-
plying it; the vessels of the uterus soon col-
lapse, when distention no longer disturbs
them; the whole viscus loses its former ex-
pansibility; while the rigidity of its fibres be-
gins to lock up those orifices which discharge
the menstrual blood; and the ovaria, from
the exclusion or diminution of their contents,
lose their influence; along with which, men-
struation, together with the powers of procre-
ation, ceases. 

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Let me now take an affectionate and res-
pectful farewell of this University and its Medi-
cal Professors. May the one, while she continues
to attract the sons of science from all parts of
our growing republic, never lack the abilities
and support she now enjoys; while the others,
by their precepts and examples, continue
to inculcate and diffuse principles, both or-
namental to the man and necessary to the
physician; may they never cease to merit,
or fail to gain, the grateful tribute due to
their services.
But to the Professor of the Practice, Dr.
Kuhn, whose attentions have been no less
pleasing, than his medical advice salutary,
during my late indisposition, I feel myself
under singular and lasting obligations. To-
gether with my thanks, Sir, accept the gra-
titude and esteem of a heart truly sensible of
your favours, and ever happy of an opportu-
nity to acknowledge them.
FINIS.