THORAX. 



1061 



TABLE R. 



Indeed when these powers are the same, it 

 indicates disease. We subjoin the following 

 table of the result of these cases. (Table S.) 

 To illustrate one of the points so striking 

 in these experiments (viz., the difference be- 

 tween the inspirafory and expiratory power), 

 we refer to diagram 701., which represents by 



curves their relative position. The upper 

 line is the expiratory power, and the double 

 line below, the inspiratory power. The per- 

 pendicular lines are the different heights of 

 the cases examined. The position of these 

 curved lines indicates the power they re- 

 present, the higher the curve the greater 

 the power. The two rows of figures at the 

 bottom are the inches and tenths of inches of 

 mercury elevated. (I. for inspiration, and E. 

 for expiration.) 



According to this, at the height of 5 feet 7 

 inches, and 5 feet 8 inches, the inspiratory power 

 is greatest, and thence the inspiratory power 

 gradually decreases as the stature increases. 

 The men of 5 feet 7 inches and 8 inches 

 elevate a column of 3 inches of mercury : 

 this may be considered a healthy power ; and 

 the men of 6 feet high elevate about 2 inches 

 of mercury as their healthy power. 



Fig. 701. 



ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. 

 505152535455565758595 10 5 11 606 + 



Expiratory. 



Inspiratory. 



E. 3-28 3-36 3'23 3-15 4'32 4'33 3'8? 4'13 4'12 4'28 3'94 363 4'48 441 

 I. 2-55 2-0 2-52 2-31 2'70 2'84 2'70 3'07 2*96 2-91 2'83 2'77 '65 2'67 



Inspiratory and expiratory power in healthy cases. 



It may be asked, why connect this with 

 the height? Because it was found in six 

 collateral observations that this was the only 

 physical condition which presented a relation 

 so as to throw the experiments into an or- 

 derly position.* By TABLE S we see that the 

 respiratory power varies in different classes. 

 The "gentlemen," for instance, are below most 

 of the other classes : at the height of 5 feet 8 

 inches, they elevate by inspiration 2'35 inches 

 of mercury. This may account for the fact 

 why Dr. Hales could only raise 2 inches of 

 mercury by this effort. 



The expiratory power is normally more 

 irregular more apt to vary than the inspi- 

 ratory power. The expiratory muscles par- 

 ticipate in other duties besides that of mere 

 expiration ; the vocation of the glass-blower, 

 the trumpeter, the wrestler, the jeweller 

 (blow-pipe), and the sailor, especially call 

 these muscles into use, increasing their na- 

 tural power. They thus oftentimes become 

 excessively strong. The inspiratory muscles 

 are exclusively for supplying us with air, in 

 which act they have only to oppose the 

 uniform resistance of elasticity. The inspira- 

 tory pmver is therefore the best indication 

 of the "health" the " vis vitae? 

 As an instance of the effect of vocation chang- 



* For the other observations, see p. 1068, and 

 Med. Chir. Trans. 1846. Vol. 39. p. 143 et seq. 



ing one of the respiratory powers and not the 

 other, we may notice the Metropo'itan po- 

 lice and the Thames police. The inspiratory 

 power of these two classes is nearly equal, 

 whilst the expiratory power of the Thames 

 police exceeds that of the Metropolitan 

 police, the former using their upper extre- 

 mities, whilst the latter use their lower ex- 

 tremities most : the former chase the thief 

 by the use of the oar ; the latter by the 

 swiftness of their legs. 



Compositors and pressmen stand low 

 the former are the lowest in their respiratory 

 power ; the pressmen are much higher. The 

 order in which some of these classes come is 

 as follows : the most powerful are the 

 Thames police ; next, the sailors ; the pau- 

 pers and the gentlemen are nearly equal ; 

 and lastly, diseased cases. The two last lines 

 is the mean of the four healthiest classes, 

 the seamen, firemen, Thames police, and 

 pugilists : their maximum is 3 inches ; the 

 mean of the whole classes together is little 

 more than 2 inches. The measure of this 

 power when expressed by inches of mercury 

 appears small, yet, when hydrostatically con- 

 sidered, it is very great. Men have wondered 

 that they could not elevate more mercury in 

 the tube; but all surprise vanishes when it is 

 recollected, that, by the law of hydrostatics, 

 when a column of 3 inches height of mer- 



3 Y 3 



