252 LIFE : OUTLINES OF GENERAL BIOLOGY 



first of the sophisticated human reason. For a number of mammals 

 shed tears copiously, and the primary reason must be relatively 

 simple. 



In Danvin's Expression of the Emotions — a book far too little 

 read — some facts are given in regard to the weeping of some 

 monkeys and the Indian elephant; and other cases are known, 

 without including "crocodiles' tears", which seem to have been 

 exaggerated. 



It is a familiar experience that a flow of tears may follow a 

 strong scent, a blow, irritant particles in the eye, exposure to 

 intense cold and, in short, a great variety of stimuli. What happens 

 is an exaggeration of the normal secretion of the lachrymal gland, 

 whose ordinary function it is to moisten the surface of the eye (the 

 conjunctiva). 



Our tears issue from several ducts on the inner surface of the 

 upper eyelid, and some of them are caught by a small aperture in 

 the lower lid and pass through the lachrymal sac into the nasal 

 passage. The others, as we are all aware, overflow and roll down our 

 cheeks. 



The exaggerated secretion may clear the eyes, which is always 

 advantageous, even if you wish to give a kiss for a blow; and the 

 tears may also have their utility in the nostril, e.g. in increasing 

 olfactory sensitiveness. And apart from utility the exaggerated 

 secretion comes as a relief to changes in the blood-pressure and 

 musculature in the region of the eye and its glands. We must recall 

 the Phrynosome "weeping blood". 



It is not unusual to see strong men weeping copiously at a 

 comedy, even in response to stimuli so different as Sir Harry 

 Lauder and Prof. Leacock. We have seen people laugh till the tears 

 fplled down their cheeks; and there is also something almost sacred 

 in "tears of joy". 



Very young children cry vocally long before they shed a tear, 

 and Darwin found that a frequent age for the first true weeping 

 was about three months. 



The flow of tears in early childhood may express pain and dis- 

 tress, but it is often worked towards by a fit of screaming that 

 expresses vexation at some thwarted wish. Later on, the weeping is 

 gradually inhibited until it is only evoked by very deep emotion. 

 In many cases the muscular contractions associated with profuse 

 weeping in children may be seen in strongly emotionalised adults, 

 although the supply of tears has long since ceased. 



Although Darwin credited some mammals, like monkeys and ele- 

 phants, with a capacity for copious tears, he thought this was 

 absent in the anthropoid apes, and this is borne out by recent 

 observations. In his striking book on the Mentality of Apes, 

 Prof. Kohler distinctly says that he never saw one weep. Their 



