1872.] 



On the Respiratory Movements in Man. 



11 



II. " On the Mechanical Conditions of the Respiratory Move- 

 ments in Man." By Arthur Ransome. Communicated 

 by Dr. Sanderson, F.R.S. Received June 22, 1872. 



(Abstract.) 



The importance of an accurate measurement of the respiratory move- 

 ments has been recognized by numerous physicians, and many different 

 methods have already been in use for this purpose ; these methods, how- 

 ever, have hitherto only given either simply the gross enlargement of the 

 circumference of the chest, or the resultants of the motions of the dif- 

 ferent points on the chest-wall. Now, owing to the shape and mode of 

 articulation of the ribs, the movements of any point on either side of the 

 sternum may take place in three planes at right angles to one another, 

 and need each to be recorded separately ; and, owing to the variations in 

 healthy breathing, it is further important that all these movements should 

 be measured during one act of breathing. 



The stethometer used in the following inquiry accomplished all these 

 tasks, and measured simultaneously the three dimensions of movement 

 of any point on the chest-wall. Graphic representations of these dimen- 

 sions could also be obtained. 



It was necessary to observe forced breathing chiefly ; and it was noticed 

 that when the button of the instrument was applied either to the middle 

 of the sternum or on the end of one of the sternal ribs, the chief motions 

 were forward and upward ; that the forward motion was most equable, 

 and started much more rapidly at first than the upward movement. 



The earliest portion of the expansive act seems to be accomplished by 

 an increase of the ordinary action of the diaphragm ; then the chest gra- 

 dually swells outwards and forwards, the ribs are raised, commencing 

 usually at the lower ribs, the costal cartilages are straightened out, the 

 head and shoulders are fixed, and the spinal column is curved backwards. 

 In expiration after this effort the operation is reversed : variations in 

 this action may be brought about by disturbing emotions, habit, sugges- 

 tions from others, or antecedent ideas. Possibly, in consequence of this 

 fact, the above account differs from that given by Haller, Sabatier, Ma- 

 jendie, Hutchinson, Sibson, and others. Care was therefore taken to ascer- 

 tain its correctness, and it was tested, — 1, by fastening tapes of paper 

 round the chest, and noticing the order in which they were torn on deep 

 inspiration; 2, by simultaneous tracings of the action of the 2nd and 

 5th or 6th ribs made, by means of Dr. Burdon Sanderson's stetho-cardio- 

 graph, on both males and females. The curves so produced were then 

 carefully examined, and conclusions drawn from them as to the differ- 

 ences between male and female respiratory movements. In the Tables 

 giving the dimensions of the motions of different points on the chest hi 

 healthy adidt males, amongst other facts certain cases were noticed in 

 which the parallelism of the movements of the sternum was interfered 



