Chap. VI. WEEPING. 159 



act downwards with unusual force in expelling the con- 

 tents of the intestinal canal. 



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 gym- 

 nastic 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 con- 

 traction 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 



14 I am greatly indebted to Mr. Bowman for having 

 introduced me to Prof. Donders, and for his aid in per- 

 suading - this great physiologist to undertake the inves- 

 tigation of the present subject. I am likewise much in- 

 debted to Mr. Bowman for having given me, with the 

 utmost kindness, information on many points. 



15 This memoir first appeared in the ' Xederlandsch 

 Archief voor Genees en Xatuurkunde,' 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 expiratorv effort," in ' Archives of Medicine,' 

 edited by Dr. L. S. Beale, 1870, vol. v. p. 20. 



