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of the orbicular muscles may serve in addition to protect the eyes from too severe a jar or vibration。 I think so； because dogs and cats； in crunching hard bones； always close their eyelids； and at least sometimes in sneezing； though dogs do not do so whilst barking loudly。 Mr。 Sutton carefully observed for me a young orang and chimpanzee； and he found that both always closed their eyes in sneezing and coughing； but not whilst screaming violently。 I gave a small pinch of snuff to a monkey of the American division； namely； a Cebus； and it closed its eyelids whilst sneezing； but not on a subsequent occasion whilst uttering loud cries。
_Cause of the secretion of tears_。It is an important fact which must be considered in any theory of the secretion of tears from the mind being affected； that whenever the muscles round the eyes are strongly and involuntarily contracted in order to compress the blood…vessels and thus to protect the eyes； tears are secreted； often in sufficient abundance to roll down the cheeks。 This occurs under the most opposite emotions； and under no emotion at all。 The sole exception； and this is only a partial one； to the existence of a relation between the involuntary and strong contraction of these muscles and the secretion of tears is that of young infants； who； whilst screaming violently with their eyelids firmly closed； do not commonly weep until they have attained the age of from two to three or four months。 Their eyes； however； become suffused with tears at a much earlier age。 It would appear； as already remarked； that the lacrymal glands do not； from the want of practice or some other cause； come to full functional activity at a very early period of life。 With children at a somewhat later age； crying out or wailing from any distress is so regularly accompanied by the shedding of tears； that weeping and crying are synonymous terms。＇18＇
Under the opposite emotion of great joy or amusement； as long as laughter is moderate there is hardly any contraction of the muscles round the eyes； so that there is no frowning； but when peals of loud laughter are uttered； with rapid and violent spasmodic expirations； tears stream down the face。 I have more than once noticed the face of a person； after a paroxysm of violent laughter； and I could see that the orbicular muscles and those running to the upper lip were still partially contracted； which together with the tear…stained cheeks gave to the upper half of the face an expression not to be distinguished from that of a child still blubbering from grief。 The fact of tears streaming down the face during violent laughter is common to all the races of mankind； as we shall see in a future chapter。
In violent coughing especially when a person is half…choked； the face becomes purple； the veins distended； the orbicular muscles strongly contracted； and tears run down the cheeks。 Even after a fit of ordinary coughing； almost every one has to wipe his eyes。 In violent vomiting or retching； as I have myself experienced and seen in others； the orbicular muscles are strongly contracted； and tears sometimes flow freely down the cheeks。 It has been suggested to me that this may be due to irritating matter being injected into the nostrils； and causing by reflex action the secretion of tears。 Accordingly I asked one of my informants； a surgeon； to attend to the effects of retching when nothing was thrown up from the stomach； and； by an odd coincidence； he himself suffered the next morning from an attack of retching； and three days subsequently observed a lady under a similar attack； and he is certain that in neither case an atom of matter was ejected from the stomach； yet the orbicular muscles were strongly contracted； and tears freely secreted。 I can also speak positively to the energetic contraction of these same muscles round the eyes； and to the coincident free secretion of tears； when the abdominal muscles act with unusual force in a downward direction on the intestinal canal。
＇18＇ Mr。 Hensleigh Wedgwood （Dict。 of English Etymology； 1859； vol。 i。 p。 410） says； 〃the verb to weep comes from Anglo…Saxon _wop_； the primary meaning of which is simply outcry。〃
Yawning commences with a deep inspiration； followed by a long and forcible expiration； and at the same time almost all the muscles of the body are strongly contracted； including those round the eyes。 During this act tears are often secreted； and I have seen them even rolling down the cheeks。
I have frequently observed that when persons scratch some point which itches intolerably； they forcibly close their eyelids； but they do not； as I believe； first draw a deep breath and then expel it with force； and I have never noticed that the eyes then become filled with tears； but I am not prepared to assert that this does not occur。 The forcible closure of the eyelids is； perhaps； merely a part of that general action by which almost all the muscles of the body are at the same time rendered rigid。 It is quite different from the gentle closure of the eyes which often accompanies； as Gratiolet remarks；＇19＇ the smelling a delicious odour； or the tasting a delicious morsel； and which probably originates in the desire to shut out any disturbing impression through the eyes。
＇19＇ ‘De la Physionomie；' 1865； p。 217。
Professor Donders writes to me to the following effect： 〃I have observed some cases of a very curious affection when； after a slight rub （_attouchement_）； for example； from the friction of a coat； which caused neither a wound nor a contusion； spasms of the orbicular muscles occurred； with a very profuse flow of tears； lasting about one hour。 Subsequently； sometimes after an interval of several weeks； violent spasms of the same muscles re…occurred； accompanied by the secretion of tears； together with primary or secondary redness of the eye。〃 Mr。 Bowman informs me that be has occasionally observed closely analogous cases； and that； in some of these； there was no redness or inflammation of the eyes。
I was anxious to ascertain whether there existed in any of the lower animals a similar relation between the contraction of the orbicular muscles during violent expiration and the secretion of tears； but there are very few animals which contract these muscles in a prolonged manner； or which shed tears。 _The Macacus maurus_； which formerly wept so copiously in the Zoological Gardens； would have been a fine case for observation； but the two monkeys now there； and which are believed to belong to the same species； do not weep。 Nevertheless they were carefully observed by Mr。 Bartlett and myself； whilst screaming loudly； and they seemed to contract these muscles； but they moved about their cages so rapidly； that it was difficult to observe with certainty。 No other monkey； as far as I have been able to ascertain； contracts its orbicular muscles whilst screaming。
The Indian elephant is known sometimes to weep。 Sir E。 Tennent； in describing these which he saw captured and bound in Ceylon； says； some 〃lay motionless on the ground； with no other indication of suffering than the tears which suffused their eyes and flowed incessantly。〃 Speaking of another elephant he says； 〃When overpowered and made fast； his grief was most affecting； his violence sank to utter prostration； and he lay on the ground； uttering choking cries； with tears trickling down his cheeks。〃＇20＇ In the Zoological Gardens the keeper of the Indian elephants positively asserts that he has several times seen tears rolling down the face of the old female； when distressed by the removal of the young one。 Hence I was extremely anxious to ascertain； as an extension of the relation between the contraction of the orbicular muscles and the shedding of tears in man； whether elephants when screaming or trumpeting loudly contract these muscles。 At Mr。 Bartlett's desire the keeper ordered the old and the young elephant to trumpet； and we repeatedly saw in both animals that； just as the trumpeting began； the orbicular muscles； especially the lower ones； were distinctly contracted。 On a subsequent occasion the keeper made the old elephant trumpet much more loudly； and invariably both the upper and lower orbicular muscles were strongly contracted； and now in an equal degree。 It is a singular fact that the African elephant； which； however； is so different from the Indian species that it is placed by some naturalists in a distinct sub…genus； when made on two occasions to trumpet loudly； exhibited no trace of the contraction of the orbicular muscles。
＇20＇ ‘Ceylon；' 3rd edit。 1859； vol。 ii。 pp。 364； 376。 I applied to Mr。 Thwaites； in Ceylon； for further information with respect to the weeping of the elephant； and in consequence received a letter from the Rev。 Mr Glenie； who； with others； kindly observed for me a herd of recently captured elephants。 These； when irritated； screamed violently； but it is remarkable that they never when thus screaming contracted the muscles round the eyes。 Nor did they shed tears； and the native hunters asserted that they had never observed elephants weeping。 Nevertheless； it appears to me impossible to doubt Sir E。 Tennent's distinct details about their weeping； supported as they are by the positive assertion of the keeper in the Zoo