One condition which we have been accus tomed to look upon as affecting our breathing, does not affect it, viz. old pleuritic adhesions.
We met with a case in which the lungs could not, in consequence of pleuritic adhe sions, be removed from out of the thorax ; in deed there was not one square inch of pleura which was not firmly adherent. The lungs had to be torn out by little pieces, and so strong was the adhesion to the diaphragm, that in removing them this muscle was ruptured, yet the living respiratory mobility of the thoracic walls exceeded by three inches the whole thoracic space allotted for the heart and lungs, as measured after death. This space to the mobility was as 248 to 251, In other respects the lungs were healthy.
Of all diseases, phthisis pulmonalis most readily affects the vital capacity, not only when the lungs are beginning to be infiltrated with tubercular matter, but probably before this.
This is shown in fig. 710. Taking all the cases together, the difference is about 50 per cent.
The effect of this disease upon the vital capacity ,in the case of Freeman was very remarkable. This man came from America in 1842 "trained for a prize fight." He was examined when in his "best condition," and his vital capacity measured 434 cub. in. (temp. 60°) ; height, 6 ft. 11i in. ; weight, 19 st. 5 lbs. ; circumference of the chest, 47 in.; inspiratory Power, 5.0 in. ; expiratory power, 6.5 in. Freeman fought his battle, and for the sub sequent two years a rambling and dissolute life. In November, 1844, exactly two years afterwards, he came to town in ill health. At this time there was no ausculta tory evidence of phthisis pulmonalis ; but the following difference appeared in his vital capacity-volume: In October, 1845, he died at the Winches ter hospital ; and Mr. Paul, surgeon to that charity, stated that Freeman died of extreme exhaustion and debility, expectorating pus ; and that his lung was throughout studded with tubercles ; his weight at death was 10 st. 1 lb. ; height, 6 ft. 7* in. Another remark able case was that of a man of perfectly healthy appearance, and in whom there was no auscultatory or general sign of organic disease, but whose vital capacity was deficient by 47 cub, in.; and it was found, within three
days of the dine when he was examined, that the left lung at the apex was studded with miliary tubercles, the whole not extending beyond a square inch.
In diseases of the spine, particularly in angular Curvature, the mobility is changed sometimes to such a degree that the vital capacity is diminished to 20 cub. in. A full meal will even make a difference in the thora cic mobility, of from 12 to 20 cubic inches. If the vital capacity is deficient, there must be some cause producing the effect. It may or may not be in the thoracic cavity. Collateral observations must point more definitely to the diseased part. The spirometer is only a gauge to measure the mobility and perme ability of the lung; other circumstances must point out the cause of the mobility and per meability being affected. Taking the observa tions upon the diseased cases by calculation,, the vital capacity volume may be arranged for all heights as follows :* The question naturally arises, How far defi cient of the standard may be the vital capacity without indicating disease ? It has been found that ten cubic inches below the due quantity, i. e. 220 instead of 230 inches, need not excite alarm ; but there is a point of deficiency in the breathing volume at which it is difficult to say whether it is merely one of those physiological differences dependent on a certain irregularity in all such observations, or deficiency indicative of disease. A deficiency of 16 per cent. is sus picious. A man below 55 years of age breath ing 193 cub. in. instead of 230 cub. in., unless he is excessively fat, is probably the subject of disease.
• In phthisis pulmonalis the deficiency may amount to 90 per cent., and yet life be main tained. The vital capacity volume is likewise a measure of improvement. A phthisical patient may improve so as to gain 40 upon 220 cub. in.