Some curious cases have been recorded in the case of women； of the power of the mind on the mammary glands； and still more remarkable ones in relation to the uterine functions。＇39＇
＇35＇ ‘Chapters on Mental Physiology；' 1858； p。 111。 ＇36＇ ‘Mind find Brain；' vol。 ii。 1860； p。 327。 ＇37＇ ‘Chapters on Mental Physiology；' pp。 104…106。 ＇38＇ See Gratiolet on this subject； De la Phys。 p。 287。 ＇39＇ Dr。 J。 Crichton Browne； from his observations on the insane； is convinced that attention directed for a prolonged period on any part or organ may ultimately influence its capillary circulation and nutrition。 He has given me some extraordinary cases； one of these； which cannot here be related in full； refers to a married woman fifty years of age； who laboured under the firm and long…continued delusion that she was pregnant。 When the expected period arrived； she acted precisely as if she had been really delivered of a child； and seemed to suffer extreme pain； so that the perspiration broke out on her forehead。 The result was that a state of things returned； continuing for three days； which had ceased during the six previous years。 Mr。 Braid gives； in his ‘Magic； Hypnotism；' &c。； 1852； p。 95； and in his other works analogous cases； as well as other facts showing the great influence of the will on the mammary glands； even on one breast alone。
When we direct our whole attention to any one sense； its acuteness is increased；＇40＇ and the continued habit of close attention； as with blind people to that of hearing； and with the blind and deaf to that of touch； appears to improve the sense in question permanently。 There is； also； some reason to believe； judging from the capacities of different races of man； that the effects are inherited。 Turning to ordinary sensations； it is well known that pain is increased by attending to it； and Sir B。 Brodie goes so far as to believe that pain may be felt in any part of the body to which attention is closely drawn。＇41＇ Sir H。 Holland also remarks that we become not only conscious of the existence of a part subjected to concentrated attention； but we experience in it various odd sensations。 as of weight； heat； cold； tingling； or itching。＇42＇
Lastly； some physiologists maintain that the mind can influence the nutrition of parts。 Sir J。 Paget has given a curious instance of the power； not indeed of the mind； but of the nervous system； on the hair。 A lady 〃who is subject to attacks of what is called nervous headache； always finds in the morning after such an one； that some patches of her hair are white； as if powdered with starch。 The change is effected in a night； and in a few days after； the hairs gradually regain their dark brownish colour。＇43＇
＇40＇ Dr。 Maudsley has given （‘The Physiology and Pathology of Mind；' 2nd edit。 1868； p。 105）； on good authority； some curious statements with respect to the improvement of the sense of touch by practice and attention。 It is remarkable that when this sense has thus been rendered more acute at any point of the body； for instance； in a finger； it is likewise improved at the corresponding point on the opposite side of the body。
＇41＇ The Lancet；' 1838； pp。 39…40； as quoted by Prof。 Laycock； ‘Nervous Diseases of Women；' 1840； p。 110。
＇42＇ ‘Chapters on Mental Physiology；' 1858； pp。 91…93。
We thus see that close attention certainly affects various parts and organs； which are not properly under the control of the will。 By what means attentionperhaps the most wonderful of all the wondrous powers of the mindis effected； is an extremely obscure subject。 According to Muller；＇44＇ the process by which the sensory cells of the brain are rendered； through the will； susceptible of receiving more intense and distinct impressions； is closely analogous to that by which the motor cells are excited to send nerve…force to the voluntary muscles。 There are many points of analogy in the action of the sensory and motor nerve…cells； for instance； the familiar fact that close attention to any one sense causes fatigue； like the prolonged exertion of any one muscle。＇45＇ When therefore we voluntarily concentrate our attention on any part of the body； the cells of the brain which receive impressions or sensations from that part are； it is probable； in some unknown manner stimulated into activity。 This may account； without any local change in the part to which our attention is earnestly directed； for pain or odd sensations being there felt or increased。
＇43＇ ‘Lectures on Surgical Pathology；' 3rd edit。 revised by Prof。 Turner； 1870； pp。 28； 31。
＇44＇ ‘Elements of Physiology；' Eng。 translat。 vol。 ii。 p。 938。
＇45＇ Prof。 Laycock has discussed this point in a very interesting manner。 See his ‘Nervous Diseases of Women；' 1840； p。 110。
If； however； the part is furnished with muscles； we cannot feel sure； as Mr。 Michael Foster has remarked to me； that some slight impulse may not be unconsciously sent to such muscles； and this would probably cause an obscure sensation in the part。
In a large number of cases； as with the salivary and lacrymal glands； intestinal canal； &c。； the power of attention seems to rest； either chiefly； or as some physiologists think； exclusively； on the vaso…motor system being affected in such a manner that more blood is allowed to flow into the capillaries of the part in question。 This increased action of the capillaries may in some cases be combined with the simultaneously increased activity of the sensorium。
The manner in which the mind affects the vasomotor system may be conceived in the following manner。 When we actually taste sour fruit； an impression is sent through the gustatory nerves to a certain part of the sensorium； this transmits nerve…force to the vasomotor centre； which consequently allows the muscular coats of the small arteries that permeate the salivary glands to relax。 Hence more blood flows into these glands； and they secrete a copious supply of saliva。 Now it does not seem an improbable assumption； that； when we reflect intently on a sensation； the same part of the sensorium； or a closely connected part of it； is brought into a state of activity； in the same manner as when we actually perceive the sensation。 If so； the same cells in the brain will be excited； though； perhaps； in a less degree； by vividly thinking about a sour taste； as by perceiving it； and they will transmit in the one case； as in the other； nerve…force to the vaso…motor centre with the same results。
To give another； and； in some respects； more appropriate illustration。 If a man stands before a hot fire； his face reddens。 This appears to be due； as Mr。 Michael Foster informs me； in part to the local action of the heat； and in part to a reflex action from the vaso…motor centres。＇46＇ In this latter case； the heat affects the nerves of the face； these transmit an impression to the sensory cells of the brain； which act on the vaso…motor centre； and this reacts on the small arteries of the face； relaxing them and allowing them to become filled with blood。 Here； again； it seems not improbable that if we were repeatedly to concentrate with great earnestness our attention on the recollection of our heated faces； the same part of the sensorium which gives us the consciousness of actual heat would be in some slight degree stimulated； and would in consequence tend to transmit some nerve…force to the vaso…motor centres； so as to relax the capillaries of the face。 Now as men during endless generations have had their attention often and earnestly directed to their personal appearance； and especially to their faces； any incipient tendency in the facial capillaries to be thus affected will have become in the course of time greatly strengthened through the principles just referred to； namely； nerve…force passing readily along accustomed channels； and inherited habit。 Thus； as it appears to me； a plausible explanation is afforded of the leading phenomena connected with the act of blushing。
_Recapitulation_。Men and women； and especially the young； have always valued； in a high degree； their personal appearance； and have likewise regarded the appearance of others。 The face has been the chief object of attention； though； when man aboriginally went naked； the whole surface of his body would have been attended to。 Our self…attention is excited almost exclusively by the opinion of others； for no person living in absolute solitude would care about his appearance。 Every one feels blame more acutely than praise。 Now； whenever we know； or suppose； that others are depreciating our personal appearance； our attention is strongly drawn towards ourselves； more especially to our faces。 The probable effect of this will be； as has just been explained； to excite into activity that part of the sensorium； which receives the sensory nerves of the face； and this will react through the vaso…motor system on the facial capillaries。 By frequent reiteration during numberless generations； the process will have become so habitual； in association with the belief that others are thinking of us； that even a suspicion of their depreciation suffices to relax the capillaries； without any conscious thought about our faces。 With some sensitive persons it is enough even to notice their dress to produce the same effect。 Through the force； also； of association and inheritance our capillaries are relaxed； whenever we know； or imagine； that any one is blaming； though in silence； our actions； thoughts； or character； and； again； when we are highly praised。
＇46＇ See； also； Mr。 Michael Foster； on the action of the vaso…motor system； in his interesting Lecture before the royal Institution； as translated in the ‘Revue des Cours Scientifiques；' Sept。 25； 1869； p。 683。
On this hypothesis we can understand how it is that the face blushes much more than any other part of the body； though the whole surface is somewhat affected； more especially with the races which still go nearly naked。 It is not at all surprising that the dark…coloured races should blush； though no change of colour is visible in their skins。 From the principle of inheritance it is not surprising that persons born blind should blush。 We can understand why the young are much more affected than the old； and women more than men； and wh