The secretion of milk may be entirely checked by mental emotions, especially those having reference to the offspring. Thus a mother sees her infant in sudden danger, either from illness or accident ; the secretion is entirely suspended, and does not return until the child, having been restored to her safe and sound, is applied to the breast. The death of the infant will frequently occasion the sudden and complete cessation of the secretion. The same result will sometimes happen from powerful emotions unconnected with the infant : thus Sir A. Cooper mentions two instances in which the secredon, though previously abundant, was suddenly arrested by terror. It has been observed by medical men who practise much among the poor, that the apprehension of the brutaal conduct of a drunken husband will put a stop for the time to the secretion of milk ; the breast feels hard and knotted, and flaccid from the ab sence of the fluid ; and some time elapses before the proper amount returns. It may be stated, generally, that whilst a tranquil, cheer ful state of mind has a tendency to increase the secretion, the depressing emotions diminish it.
The mere increase or diminution of the secretion, from an influence communicated through the nerves, may possibly be accounted for by the influence they seem to exercise over the calibre of the smaller arteries, as shown in the act of blushing, to which " the draught" seems to have considerable resem blance. But no such explanation accounts for the important fact, that not only the quan tity but the quality of the milk is changed by mental emotions. Grief', anxiety, fits of anger, or a continual fretfulness, tend to render the milk thin and serous, and to impart to it qualities that excite intestinal irritation, griping, and fever in the child that ingests it. It might be difficult to detect any noxious elements in it by chemical analysis ; but the effect of the fluid upon the delicate system of the infant is a sure indication of their ex istence. With this knowledge, derived from almost daily observation, we can have no reasonable ground for refusing to credit ac counts of still more remarkable results pro ceeding from the influence of mental emotion on the mainmary secretion, such as the fol lowing :—" A carpenter fell into a quarrel with a soldier billeted in his house, and was set upon by the latter with his drawn sword. The wife of the carpenter at first trembled from fear and terror, and then suddenly threw herself furiously between the com batants, wrested the sword from the soldier's hand, broke it in pieces, and threw it away. Durinff the tumult. some neighbours came in and separated the men. While in this state of strong excitement, the mother took up her child from the cradle, where it lay playing and in the most perfect health, never having had a moment's illness ; she gave it the breast and in so doing sealed its fate. In a few minutes the infant left off sucking, became restless, panted, and sank dead upon its mother's bosom. The physician who was instantly, called in, found the child lying in the cradle as if asleep, and with its features un disturbed ; but all his resources were fruitless. It was irrecoverably gone."* Such a case might be regarded as a mere coincidence if it stood alone ; but several others of similar character are upon record. Mr. Wardrop mentions t that having removed a small tu mour from behind the ear of a mother, all went well until she fell into a violent passion, and the child being suckled soon afterwards, died in convulsions. Ile was sent for hastily to see another child in convulsionk after taking the breast of a nurse who had just been severely reprimanded; and he was informed by Sir Richard Croft that he had seen many similar instances. Burdach cites two cases of a similar kind ; in one of which the infant put to the breast of its mother, just as she had received some very alarming intelligence, died in her arms before the eyes of the mes senger ; hilst in the other, the child having been nursed when the mind of the mother was in violent agitation, suddenly became extremely pale, and after sotne hours was attacked with paralysis on the right side, and convulsions on the left. Another of a very similar character has been more recently put on record. " A woman while suckling her child became violently excited by the loss of some article which had been stolen from her.
She gave her child the breast while in a state of violent passion. The child at first re jected it, but subsequently took a quantity of milk. Soon afterwards violent vomiting supervened. In the course of some hours, the child took the other breast, when it was attacked with violent convulsions, and died in spite of medical aid." t It will not be requisite to enter into similar details in regard to other secretions, the in fluence of emotional states on which is a familiar fact. Thus the flow of saliva is stimulated by the sight, the smell, the taste, or even by the idea, of food ; whilst it may be entirely arrested by strong emotion, as is shown by the well known test often resorted to in India for the discovery of a thief among the servants of a family. All the parties being compelled to hold a certain quantity of rice in the mouth during a few minutes, the offender is generally distinguished by the com parative dryness of his mouthful at the end of the experiment. The gastric secretion is greatly influenced by the emotional states being usually increased by moderate exhilara tion, and diminished by depression of the feel ings. Any very strong emotion, however, usually suspends it for a time. The lachrymalsecretion, which is continually being formed to a small extent for the purpose of bathing the surface of the eye, is poured out in great abundance under the moderate excitement of the emo tions, either of joy, tenderness, or grief. It is checked, however, by violent emotions : hence in intense grief the tears do not flow. It is a well known proof of moderated sorrow when the flow returns : tears, however, do not bring relief, as commonly supposed, but they indicate that the violence of the emotion has passed off. The odoriferous secretion from the skin, which is much more powerful in some individuals than in others, is increased under the influence of certain mental emo tions, such as fear or bashfulness, and com monly also by sexual desire.* That the formation of this secretion is due to changes occurring in the blood itself, and that the function of the cutaneous glandul is rather to eliminate than to produce it, would appear from the fact that the characteristic smell of different animals may be detected in their blood when it is treated with sulphuric acid. The influence of fear or of sexual desire on the odoriferous secretions of many of the lower animals is well known ; the emission of a powerful and disgusting smell being not un frequently a chief means of defence. The odoriferous matter is sometimes poured into the internal cavities, and discharged with the normal excretions, imparting to them its peculiar scent: thus the urine of a cat, voided under the influence of alarm, possesses a strong and disagreeable smell, which is with difficulty got rid of. The halitus from the lungs is in some persons so affected.by mental emotions, that a piece of bad news shall almost instantaneously produce fcetid breath. A copious secretion of fcetid gas not un frequently takes place in the intestinal canal, under the influence of any disturbing emo tion ; or the usual liquid secretions from its walls are similarly disordered. The tendency to defxcation, which is commonly excited under such circurnstances, is not simply due therefore to relaxation of the sphincter ani, as commonly supposed, but is partly dependent on the unusually stimulating character of the fces themselves. It is a prevalent, and, perhaps, not an ill-founded, opinion, that me lancholy and jealousy have a tendency to in crease the quantity, and to vitiate the quality, of the biliary fluid ; and amongst the causes of jaundice are usually set down the indul gence of the depressing emotions, or an access of sudden and violent passion. There can be no doubt, however, that a disordered state of the biliary secretion is frequently rather the cause than the consequence of a melan cholic state of mind ; the blood being suffi ciently vitiated by a deficient elimination of bile, to have its due relations with the nervous system seriously disturbed, before any ob vious indications of that deficiency make their appearance in the jaundiced aspect of the cntaneous surface.