392 



Royal Society : — 



measures the rise and fall of the chest in respiration. It Hkewise 

 declares the relative duration of inspiration and expiration, and may 

 thus prove useful in the detection of incipient phthisis, and other 

 pulmonary diseases. When the liquid has attained its highest eleva- 

 tion at the end of inspiration, it immediately begins to fall ; but when 

 it has reached the lowest point at the end of expiration, it remains 

 there some instants. The ascent is slower than the descent. After the 

 fall of an ordinary expiration, a forced expiration gives a second fall. 



The sphygmoscope may be employed without a stand and is then 

 more portable (fig. 3), but from the want of a fixed basis, and 

 from the motion of the ribs on which it must rest, its manifesta- 

 tions are less extensive and satisfactory. It may be maintained in 

 situ with an elastic band placed around the thorax. When em- 

 ployed without a stand, as it must rest upon the Fig. 3. 

 ribs, the elastic wall of the chamber should be 

 plain, and not protruding. 



The hand-sphygmoscope is an exceedingly 

 delicate instrument, but requires great care and 

 nicety in its construction. It may be made by 

 taking about an inch and a half of a gutta percha 

 tube, half an inch in diameter, slightly widening 

 one extremity of it to make a chamber large 

 enough to hold a small horse-bean, and fastening 

 with thread a piece of thin india-rubber, or of 

 Bourgeaud's india-rubber bandage, securely over 

 it for the elastic and moveable wall. The liquid is 

 now supplied, and the glass tube, with a very fine 

 flat bore, say ^V^^ ^^ ^^ inch, and provided with 

 a ring of india-rubber, obtained by cutting oiF a 

 small portion of a fine india-rubber tube, for a 

 "washer," is now inserted and the instrument is 

 ready for use. The hand-sphygmoscope discovers 

 the blood-wave in regurgitation of the jugular 

 veins ; it responds to the radial of the newly- 

 born infant ; it rises and falls with the movements 

 of the brain of the infant, though some months 

 old, as that organ rises and falls under the influ- 

 ence of its arteries. There is no doubt that, ap- 

 plied to the fontanelles before delivery, it will Portable Sphyemo- 

 inform the obstetrician whether the foetus be dead scope. 



or alive, and, in cases of diflicult labour, supply important evidence 

 for his guidance. 



The hand-sphygmoscope apphed to the radial artery, and to the 

 fontanelles of a dying infant three months old, has indicated to the 

 author the influence of respiration upon the circulation. During 

 inspiration, the column of liquid in the tube was found to fall as if 

 sucked down, and during expiration to spring again. 



In practical surgery, the hand-sphygmoscope may possibly be 

 employed with advantage, for it will rise with the wave or fluctuation 

 of liquid tumours. It may be placed where the fingers cannot reach. 



