Although Dr. Browne has often seen this muscle quivering and contracting in the insane, he has not been able to connect its action with any emotional condition in them, though he carefully attended to patients suffering from great fear. Mr. Nicol, on the other hand, has observed three cases in which this muscle appeared to be more or less permanently contracted under the influence of melancholia, associated with much dread; but in one of these cases, various other muscles about the neck and head were subject to spasmodic contractions.
Dr. W. Ogle observed for me in one of the London hospitals about twenty patients, just before they were put under the influence of chloroform for operations. They exhibited some trepidation, but no great terror. In only four of the cases was the platysma visibly contracted; and it did not begin to contract until the patients began to cry. The muscle seemed to contract at the moment of each deep-drawn inspiration; so that it is very doubtful whether the contraction depended at all on the emotion of fear. In a fifth case, the patient, who was not chloroformed, was much terrified; and his platysma was more forcibly and persistently contracted than in the other cases. But even here there is room for doubt, for the muscle which appeared to be unusually developed, was seen by Dr. Ogle to contract as the man moved his head from the pillow, after the operation was over.
As I felt much perplexed why, in any case, a superficial muscle on the neck should be especially affected by fear, I applied to my many obliging correspondents for information about the contraction of this muscle under other circumstances. It would be superfluous to give all the answers which I have received. They show that this muscle acts, often in a variable manner and degree, under many different conditions. It is violently contracted in hydrophobia, and in a somewhat less degree in lockjaw; sometimes in a marked manner during the insensibility from chloroform. Dr. W. Ogle observed two male patients, suffering from such difficulty in breathing, that the trachea had to be opened, and in both the platysma was strongly contracted. One of these men overheard the conversation of the surgeons surrounding him, and when he was able to speak, declared that he had not been frightened. In some other cases of extreme difficulty of respiration, though not requiring tracheotomy, observed by Drs. Ogle and Langstaff, the platysma was not contracted.
Mr. J. Wood, who has studied with such care the muscles of the human body, as shown by his various publications, has often seen the platysma contracted in vomiting, nausea, and disgust; also in children and adults under the influence of rage,--for instance, in Irishwomen, quarrelling and brawling together with angry gesticulations. This may possibly have been due to their high and angry tones; for I know a lady, an excellent musician, who, in singing certain high notes, always contracts her platysma. So does a young man, as I have observed, in sounding certain notes on the flute. Mr. J. Wood informs me that he has found the platysma best developed in persons with thick necks and broad shoulders; and that in families inheriting these peculiarities, its development is usually associated with much voluntary power over the homologous occipito-frontalis muscle, by which the scalp can be moved.
None of the foregoing cases appear to throw any light on the contraction of the platysma from fear; but it is different, I think, with the following cases. The gentleman before referred to, who can voluntarily act on this muscle only on one side of his neck, is positive that it contracts on both sides whenever he is startled. Evidence has already been given showing that this muscle sometimes contracts, perhaps for the sake of opening the mouth widely, when the breathing is rendered difficult by disease, and during the deep inspirations of crying-fits before an operation. Now, whenever a person starts at any sudden sight or sound, he instantaneously draws a deep breath; and thus the contraction of the platysma may possibly have become associated with the sense of fear.