Part 15 (1/2)

A either pain or excessive haee, render menstruation an abnormal process, and incompatible with active exertion, three are directly connected with the ganglionic system of nerves, the fourth indirectly, by the possible influence upon them of the cerebro-spinal The first are excessive activity of the ovarian nerves, derived froastric plexus; paralysis of uterine vaso-motor nerves, as a secondary result of this excessive action: exhaustion of these saeneral nervous exhaustion The last theoretical condition would be, exciteous to what alvanic current, and followed, therefore, by the same consequence--paralysis of vaso-motor nerves, and excessive dilatation of the blood-vessels

The two first conditions a these four are lionic systeanisularity, marked by vaso-motor spasree of disorder, which, if long continued, passes to the next--of vaso-e; and finally may, as Dr Clarke has pointed out, be followed by paralysis in the ovarian plexus itself, with consequent cessation of ovulation, and amenorrhea, or absence of ularity of the ganglionic nerves implies, as has been seen, a relatively deficient innervation or generation of nerve-force in the cerebro-spinal system It could not, therefore, be ascribed to excessive activity of that system, except in the cases where this has been pushed to the point of complete exhaustion It is, in fact, a matter of common observation, that hysterical and anemic women, in whom disordered menstruation is most frequently observed, are conspicuously destitute of habits i either cerebral or spinal activity--that is, they neither think much, nor take much physical exercise

The last two cases, however, of cerebro-spinal excitement or exhaustion, may be supposed to imply a predominant activity of the cerebro-spinal system

Inquiry into the effects of cerebro-spinal excitement is rendered extre facts:

1st Experialvanism or mechanical irritation, causes different results when applied to spinal nerves, to different parts of the spinal cord, or to different parts of the brain

Galvanism applied to a spinal nerve, determines, it has been said, dilatation of blood-vessels, and increased secretion in glands But galvanism applied to the spinal cord in the neck, causes contraction of blood-vessels Mechanical irritation of other parts of the spinal cord, on the other hand, causes vaso-motor paralysis and dilatation of blood-vessels This is especially true of that part lying in the loins, and which contains a peculiar nervous centre, that stands in special relation to the uterus and ovaries, and is involved in many of their diseases, either as a cause or effect Systealvanic irritation of the brain has been little attempted, until in some very recent experiments; but its effects are already known to beto the part to which it is applied The brain is not a single organ, but rather a collection of organs, differing from one another in function eventheht

2d In the ata exists a nervous centre called the vaso-motor centre, because of its close relations with the vaso-motor nerves Stimulation of this centre causes contraction of the blood-vessels Severing the same part causes paralysis of the vaso-motor nerves and dilatation of the blood-vessels The conditions of the brain that have been most clearly shown to influence the circulation, are those that can be proved to take an effect on this vaso-motor centre

If, as is probable, different forms of cerebral action induce or depend on different cerebral conditions, or involve different sections of the cranial masses, this effect would necessarily be different, and the influence on the circulation vary accordingly

3d No experimental proof has hitherto been obtained that sti above the vaso- the function of thought, ever paralyzes this centre; but, as it is only by such paralysis that cerebral conditions can induce dilatation of blood-vessels, it must follow that no _experimental proof_ at present exists that stimulation of the brain ever does cause such dilatation--that is, ever does becoe The _clinical_ facts for such a supposition are those in which the occurrence of an e of the face, acceleration of the pulse, hot or cold perspirations, phenomena all indicative of dilatation of the blood-vessels, with temporary paralysis of their nerves and of their vaso-motor centre It is not proved, however, that the e these effects really result froenerally accompanied by diminished activity of that cerebral function that most certainly does depend on such stiht

Now, since the power of thought and the power of the vaso-motor centre are equally paralyzed under these circumstances, it is more probable that the phenomena which most nearly resemble those of stimulation of the brain are either confined to soonism to the rest, or else are really phenoory But if these do not, no facts exist to prove that stimulation of the intellectual functions of the brain is in itself capable of producing vaso-e; or, in other words, stialvanic stimulation of a spinal nerve But if stimulation of the brain does not paralyze, it must increase the tonicity of the vaso-ularity of the circulation Up to a certain point, these characters do indeed increase, with increase of pressure in the cerebral blood-vessels They increase also during intellectual operations, unattended by emotion, in which a similar increase of pressure must take place, on account of the afflux of blood to the cerebral hemispheres, when these are aroused to activity

These facts already indicate a radical difference between the nature of the cerebral actions involved in eht From them also we should infer in all cases where vaso-motor paralysis was apparently traceable to excess of cerebral activity, either _that exhaustion had already occurred, or that the activity was not intellectual but eht to our fourth possible condition for uterine haee, dependent on modifications of the cerebro-spinal system It is adical observations that need not here be quoted, that exhaustion of certain parts of the brain and spinal cord may induce vaso-e is already in operation, a passive flow of blood may be indefinitely increased Such a course is the menstrual crisis, without which even the vaso-motor paralysis is usually unable to detere[40] In connection with it, physical exercise, pushed to the point of exhausting the spinal cord, and the peculiar centre in its lued as to exhaust the brain, and the general vaso-ia

It is evident, however, that if such exhaustion had been produced previous to the menstrual epoch, the effect would be precisely the same as if the morbific causes operated only at the time of gested by Dr Clarke, of inter the menstrual period, would be inadequate whenever it was not superfluous But in Dr Clarke's theory this period has a peculiar influence in rendering morbific conditions that at other times are innocuous This, in virtue of the law already quoted, that the evolution of force at one centre of the nervous system is incompatible with an evolution of equal intensity at another, since it diminishes the sum of resources distributed to the nervous system as a whole Hence, relatively to the amount of power left in the brain, the sa, and may easily lead to exhaustion with all its consequences

Nothing seems more siical problems are complicated by the element of quantity--circu absolute assertions The coestion and that of menstruation should suffice to show that there is no absolute incolionic centres and at the cerebro-spinal For if so the process of digestion would necessitate such absolute torpor of the brain and spinal cord as certainly would be quite incoencies of civilized life There is a certain alternation between the periods of activity of the two systeestive torpor of the savage, analogous to that of ruestion of healthy men of temperate habits and marked intellectual and physical activity, to whom all hours of the day are nearly equally suitable for exertion As previously said, up to a certain point, the incompatibility diminishes with every increase in the developain, the evolution of nerve force required by ovulation should not normally be comparable in intensity with that effected in cerebral or spinal action Whenever it is so the activity of the ganglionic system must be in excess, or that of the cerebro-spinal systehly civilized societies, one or both of these conditions very frequently exist, but it is then as truly abnormal as is the dyspepsia and spleen--equally prevalent

Although, for certain purposes, it is necessary to consider the ganglionic and cerebro-spinal systele apparatus, it is important also to remember the boundaries that lie between them It is much easier, by intense muscular exertion, that necessitates evolution of force in the spinal cord, to render the brain incapable of function, than to do so by intense action of the ganglionic nerves, whose connection with the brain, though real, is much less direct Were it not so, life would be much more precarious than it is, and advance in civilization impossible; because the necessarily incessant activity of the nerves involved in nutritive processes would too largely impair the action of the brain The effect on the brain of a really irresistible and predoans, is to be studied in the lower animals, and in phenomena that, fortunately, are rarely to be observed in healthy individuals of the human race Still less can such confessedly morbid predominance be considered as a peculiar liability of the feular tendency exists in ly manifested in Dr Clarke's book, to assu to sex and to the functions of reproduction exercise such an enormous influence upon one sex, and none at all upon the other Since the discovery in 1827 of the ovule or female reproductive cell, there can be no question of the coy between the essential organs of reproduction in the two sexes The period of their development, the influence of such developularities of nutritive or of cerebro-spinal action, that ularities in such developan of gestation that is peculiar to the feh resulting fros to the race In a double sense is the uterus secondary to the ovaries[41] For its physiological action, both in nancy, is the direct consequence of ovarian functions, and closely dependent upon them; and the period of its prominent activity does not come until after the action of the ovaries has been completely established; that is, the period of maternity is, or should be, consecutive to the period of adolescence, and the work of gestation only entered upon when the work of ovulation has long been thoroughly accoies have been much overstrained that exist between the nancy of an adult woical law that in soht be called a caprice of nature, in virtue of which the rudiments of a process that is to be effected at a future epoch are sketched out during an epoch already existing The afflux of blood to the uterus during the rupture of the ovisac, cannot be shown to be useful by any effort of teleological physiologists It predicts, however, the afflux that will be necessary at a future pregnancy, in precisely the sas in the foetus predicts the future necessity for respiration, or the forirl, predicts the future necessity of a reproductive apparatus But to iirl the precautions necessary to the e her

In the same way is the child enfeebled by preard to sex that do not yet exist, and the adult woman so often treated as old as soon as she has borne children, which should be a proof not of age, but ofconsiderations we may, we think, conclude:

1st That unless the brain and spinal cord _had been already exhausted or on the point of exhaustion previous to the menstrual_ crisis, this alone would be insufficient to exhaust theree of exhaustion in the cerebro-spinal systereat, and much transcends that likely to be induced by the irl's school

3d That therefore, when vaso-e, has occurred apparently in consequence of such mental exertion, it is really due to so with this

Of these we have already insisted upon two--sedentary position and deficiency of physical exercise

Authors have less frequently analyzed the effects of another circu the intellectual exertions of school life, namely, the morbid emotional excitement that is incident either to the period of adolescence or to the injudicious educational _regime_ To precisely appreciate these effects, it will be necessary to push a little further the analysis already commenced, of the mode of activity exhibited by different portions of the brain during the evolution of thought or of e this subject, a few facts are, nevertheless, demonstrated The first that concerns us is the existence of the vaso-motor centre, whose situation and functions have been already described The second is the localization of the function of thought in the circuray matter on the surface of the cerebral hemispheres--fact that we have already assumed to be sufficiently demonstrated The third class of facts include those, also insisted upon, that indicate a peculiar influence of the emotions upon the circulation and the vaso-motor nerves In some cases these are stimulated, and the blood-vessels spasrow cold, chills creep down the back--even nausea may occur from interference with the circulation of the brain; or else the cheek flushes, the temples throb, the heart beats more rapidly, when, from temporary paralysis of these same nerves, the blood-vessels are suddenly dilated

These phenoeneration of emotion, is in closer connection with the cerebral vaso-motor centre than is the seat of ideas

From this positive stand-point we may be permitted to cautiously venture a little further, in the direction of a theory for the precise localization of the organs of emotion

It is well known that at the base of the brain are collected certain masses of nervous lia, that are in very intimate connection, on the one hand, with nerves of special sense, as the optic[42] and olfactory,[43] on the other with nerves of general sensation and motion[44] To this intricate part of the brain, these centres, converge the nerve-fibres collected in the spinal cord and ata, and froent course, and finally terray matter of the cerebral heht from the periphery of the body, are conveyed to special foci of concentration, thence to be transray matter at the surface of the brain, and becoenerated in the nerve-cells devoted to the elaboration of thought, pass through these same intermediate stations before they acquire sufficient consistency to affect the h them, the muscular osseous apparatus of the body Before a sensory iht, or a voluntary ied toward these centres, whence it afterwards radiates, along divergent fibres, directed now above, to the surface of the brain, now below, on a longer course, to the surface of the body