222 APPLIED PHYSIOLOGY 



When the mind is much preoccupied, the breathing 

 becomes feeble, and this has to be compensated by a 

 few deep inspirations, which take the form of ' sighs.' 

 It is the result, therefore, of a spell of ' breathless 

 attention.' 



'The philosopher brooding over his problem,' says 

 Lewes,* ' will be heard sighing from time to time, 

 almost as deeply as the maiden brooding over her forlorn 

 condition. All men sigh over their work when their 

 work deeply engages them ; but they do not remark 

 it, because the work, and not their feelings, engages their 

 attention, whereas during grief it is their feelings which 

 occupy them.' 



A similar sighing respiration has been noted as the 

 result of the depression of the respiratory centre from 

 the excessive use of tobacco. 



Hiccough is the result of a spasm of the diaphragm, 

 which produces a sudden inspiration, the inrush of air 

 being as suddenly checked by closure of the glottis, 

 which produces the characteristic sound. It is often 

 the result of gastric irritation, and is a common phe- 

 nomenon in many conditions of disease. 



Sobbing" is another alteration of respiration, consisting 

 in an inco-ordination in the different parts of the pro- 

 cess. It consists in sudden inspirations, in which the 

 glottis opens a little too late, the inrush of air producing 

 the familiar sound. It is comparable to the crowing 

 sound produced in laryngismus stridulus. 



* c The Physiology of Common Life,' i. 399. 



