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res of the orbicularis； and this is a provision for supporting and defending the vascular system of the interior of the eye from a retrograde impulse communicated to the blood in the veins at that time。 When we contract the chest and expel the air； there is a retardation of the blood in the veins of the neck and head； and in the more powerful acts of expulsion； the blood not only distends the vessels； but is even regurgitated into the minute branches。 Were the eye not properly compressed at that time； and a resistance given to the shock； irreparable injury might be inflicted on the delicate textures of the interior of the eye。〃 He further adds； 〃If we separate the eyelids of a child to examine the eye； while it cries and struggles with passion； by taking off the natural support to the vascular system of the eye； and means of guarding it against the rush of blood then occurring； the conjunctiva becomes suddenly filled with blood； and the eyelids everted。〃
＇12＇ ‘The Anatomy of Expression；' 1844； p。 106。 See also his paper in the ‘Philosophical Transactions；' 1822； p。 284； ibid。 1823； pp。 166 and 289。 Also ‘The Nervous System of the Human Body；' 3rd edit。 1836； p。 175。
Not only are the muscles round the eyes strongly contracted； as Sir C。 Bell states and as I have often observed； during screaming； loud laughter； coughing； and sneezing； but during several other analogous actions。 A man contracts these muscles when he violently blows his nose。 I asked one of my boys to shout as loudly as he possibly could； and as soon as he began； he firmly contracted his orbicular muscles； I observed this repeatedly； and on asking him why he had every time so firmly closed his eyes； I found that he was quite unaware of the fact： he had acted instinctively or unconsciously。
It is not necessary； in order to lead to the contraction of these muscles； that air should actually be expelled from the chest； it suffices that the muscles of the chest and abdomen should contract with great force； whilst by the closure of the glottis no air escapes。 In violent vomiting or retching the diaphragm is made to descend by the chest being filled with air； it is then held in this position by the closure of the glottis； 〃as well as by the contraction of its own fibres。〃＇13＇ The abdominal muscles now contract strongly upon the stomach； its proper muscles likewise contracting； and the contents are thus ejected。 During each effort of vomiting 〃the head becomes greatly congested； so that the features are red and swollen； and the large veins of the face and temples visibly dilated。〃 At the same time； as I know from observation； the muscles round the eyes are strongly contracted。 This is likewise the case when the abdominal muscles act downwards with unusual force in expelling the contents of the intestinal canal。
＇13＇ See Dr。 Brinton's account of the act of vomiting； in Todd's Cyclop。 of Anatomy and Physiology； 1859； vol。 v。 Supplement； p。 318。
The greatest exertion of the muscles of the body； if those of the chest are not brought into strong action in expelling or compressing the air within the lungs； does not lead to the contraction of the muscles round the eyes。 I have observed my sons using great force in gymnastic exercises； as in repeatedly raising their suspended bodies by their arms alone； and in lifting heavy weights from the ground； but there was hardly any trace of contraction in the muscles round the eyes。
As the contraction of these muscles for the protection of the eyes during violent expiration is indirectly； as we shall hereafter see； a fundamental element in several of our most important expressions； I was extremely anxious to ascertain how far Sir C。 Bell's view could be substantiated。 Professor Donders； of Utrecht；＇14＇ well known as one of the highest authorities in Europe on vision and on the structure of the eye； has most kindly undertaken for me this investigation with the aid of the many ingenious mechanisms of modern science； and has published the results。＇15＇ He shows that during violent expiration the external； the intra…ocular； and the retro…ocular vessels of the eye are all affected in two ways； namely by the increased pressure of the blood in the arteries； and by the return of the blood in the veins being impeded。 It is； therefore； certain that both the arteries and the veins of the eye are more or less distended during violent expiration。 The evidence in detail may be found in Professor Donders' valuable memoir。 We see the effects on the veins of the head； in their prominence； and in the purple colour of the face of a man who coughs violently from being half choked。 I may mention； on the same authority； that the whole eye certainly advances a little during each violent expiration。 This is due to the dilatation of the retro…ocular vessels； and might have been expected from the intimate connection of the eye and brain； the brain being known to rise and fall with each respiration； when a portion of the skull has been removed； and as may be seen along the unclosed sutures of infants' heads。 This also； I presume； is the reason that the eyes of a strangled man appear as if they were starting from their sockets。
＇14＇ I am greatly indebted to Mr。 Bowman for having introduced me to Prof。 Donders； and for his aid in persuading this great physiologist to undertake the investigation of the present subject。 I am likewise much indebted to Mr。 Bowman for having given me； with the utmost kindness； information on many points。
＇15＇ This memoir first appeared in the ‘Nederlandsch Archief voor Genees en Natuurkiinde；' Deel 5； 1870。 It has been translated by Dr。 W。 D。 Moore； under the title of 〃On the Action of the Eyelids in determination of Blood from expiratory effort；〃 in ‘Archives of Medicine；' edited by Dr。 L。 S。 Beale； 1870； vol。 v。 p。 20。
With respect to the protection of the eye during violent expiratory efforts by the pressure of the eyelids； Professor Donders concludes from his various observations that this action certainly limits or entirely removes the dilatation of the vessels。＇16＇ At such times； he adds； we not unfrequently see the hand involuntarily laid upon the eyelids； as if the better to support and defend the eyeball。
＇16＇ Prof。 Donders remarks （ibid。 p。 28）； that； 〃After injury to the eye； after operations； and in some forms of internal inflammation； we attach great value to the uniform support of the closed eyelids； and we increase this in many instances by the application of a bandage。 In both cases we carefully endeavour to avoid great expiratory pressure； the disadvantage of which is well known。〃 Mr。 Bowman informs me that in the excessive photophobia； accompanying what is called scrofulous ophthalmia in children； when the light is so very painful that during weeks or months it is constantly excluded by the most forcible closure of the lids； he has often been struck on opening the lids by the paleness of the eye； not an unnatural paleness； but an absence of the redness that might have been expected when the surface is somewhat inflamed； as is then usually the case； and this paleness he is inclined to attribute to the forcible closure of the eyelids。
Nevertheless much evidence cannot at present be advanced to prove that the eye actually suffers injury from the want of support during violent expiration； but there is some。 It is 〃a fact that forcible expiratory efforts in violent coughing or vomiting； and especially in sneezing； sometimes give rise to ruptures of the little （external） vessels〃 of the eye。＇17＇ With respect to the internal vessels； Dr。 Gunning has lately recorded a case of exophthalmos in consequence of whooping…cough； which in his opinion depended on the rupture of the deeper vessels； and another analogous case has been recorded。 But a mere sense of discomfort would probably suffice to lead to the associated habit of protecting the eyeball by the contraction of the surrounding muscles。 Even the expectation or chance of injury would probably be sufficient； in the same manner as an object moving too near the eye induces involuntary winking of the eyelids。 We may； therefore； safely conclude from Sir C。 Bell's observations； and more especially from the more careful investigations by Professor Donders； that the firm closure of the eyelids during the screaming of children is an action full of meaning and of real service。
We have already seen that the contraction of the orbicular muscles leads to the drawing up of the upper lip； and consequently； if the mouth is kept widely open； to the drawing down of the corners by the contraction of the depressor muscles。 The formation of the naso…labial fold on the cheeks likewise follows from the drawing up of the upper lip。 Thus all the chief expressive movements of the face during crying apparently result from the contraction of the muscles round the eyes。 We shall also find that the shedding of tears depends on； or at least stands in some connection with； the contraction of these same muscles。
＇17＇ Donders； ibid。 p。 36。
In some of the foregoing cases； especially in those of sneezing and coughing； it is possible that the contraction of the orbicular muscles may serve in addition to protect the eyes from too severe a jar or vibrati