pheral extremity first, and then progressively to the central part, and permits of the most ready expansion when that act is required. When it is recollected that the alternate expansion and retraction must occur at the rate of about 1000 times per hour throughout life, and be subject to great and sudden variations of expanding force and rapidity of action, as in the case of violent exertion, it is clearly necessary that the most perfect mode of elongation and retraction should be employed. We therefore think that the anatomical arrangement which we have pointed out comports well with the requirements of the organ, and, in all probability, gives a sufficient explanation of this remarkable action. It may also be observed, that for this action it is not essential that the spire shall be in all its parts single, as in the bell spring, but the fibre may have a dichotomous or other arrangement, as in plants; and since the vesicles certainly communicate with each other, it is manifest that the uniformity of the spiral arrangement will be broken, in order to allow of the junction with other vesicles. In the figure above given, the spire was single, and nearly uniform in its arrangement: but in the sections which will commonly occupy attention, there is much less regularity than is there depicted.

Hence, on a review of the foregoing observations, we find that the structure of the lungs in no degree aids in the expansion of these organs, yet normally passively permits the expansion whilst possessing a certain power of resistance; but it is well fitted to aid in the act of retraction. It also appears that no

congenital change could confer upon it any power to aid expansion, but an abnormal arrangement might increase the natural tendency to resist expansion, and the ordinary power to effect retraction. Such also must be the effect of disease; and hence we arrive at the general conclusion that all abnormal conditions of the lungs whatever must be adverse to inspiration, and with the exception of emphysema, be favourable to expiration or both.

In the conditions met with in the early stage of phthisis, there is, as has already been shown, diminished expansion of the chest, which also implies lessened elongation, and general expansion of the air vesicles of the lung, without any diminution of the power of retraction attending expiration. It has also been shown that with this lessened amount of expansion there is also feeble inspiratory effort, and whilst the effort to expand the chest fully is less than that required to expand it to a less degree, there is a correspondence between short and feeble inspiration, and, in all probability, a more feeble motion of the air in its passage through the lungs.

CHAPTER XXII.

INTERNAL PULMONARY EVIDENCES OF EARLY PHTHISIS.

FEEBLE BREATHING.

The earliest and therefore the most universal condition is that of lessened force, and fulness of the respiratory murmur and diminished length of the ordinary inspiratory act.

Dr. Stokes remarks in reference to feebleness of respiration," of the different signs of incipient phthisis there is none more important than this," and "may occur as the sole phenomenon." In giving three causes for its production, he believes with M. Reynaud that it is commonly due to obliteration of the minute bronchical tubes. He, however, still associates it with deposition of tubercle; and it is probable from his definition of the cause of it, that he does not mean the same thing as that referred to by us. It is not necessary that there should be an irregular kind of respiration, such as would be perceived by the ear, if some of the air vesicles were pervious and others closed, as after the deposition of tubercle, but an uniform feebleness of the sound issuing from all the air vesicles equally. The condition referred to by Dr. Stokes refers, we think, to a later period.

We believe it to be a universal condition in the earliest stage of phthisis that the vesicular murmur is less strong than occurs in health. The examination may be conducted by testing both ordinary and forced inspiration. On the patient being quietly seated, and the respiration proceeding naturally, it will be found that the vesicular murmur is but indistinctly audible, and quite different from that general gentle buzzing which is so perceptibly present in health. At the same time it will be noticed that the apparent distance to which the inspired air is carried, or, in other words, the length of the inspiratory current, is shortened, and the act of inspiration is short and feeble, whilst that of expiration is perhaps shorter and quicker than is natural. On the patient inspiring forcibly the respiratory sounds are of course increased considerably in intensity, but they are more or less tubular, and the vesicular sound is much less distinct than occurs with forced inspiration in health, and there is still the same evidence of feebleness of inspiration. It also frequently occurs that the patient is unable to take a long, deep, and slow inspiration, until his attention has been repeatedly called to it, and he has been in some degree trained. Usually when he is required to inspire deeply, he makes a quick and short inspiration, and when he has overcome that source of error, the inspiration will still be feeble, and only with difficulty can he be induced to inspire deeply, and to fully expand the lungs.

It usually occurs that whilst feeble and short vesicular sounds are extensively present, they are more

perceptible on one side than on the other (Dr. Stokes and others affirm that the vesicular murmur is naturally more feeble on the right side), for it very rarely happens that the disease proceeds at an equal pace in all parts of the chest, and as the disease advances to a certain point the vesicular sounds progressively diminish in force and fullness.

It may here be demanded in what respect this change varies from that found in ordinary debility on the one hand, and from a tubercular condition on the other, and we will endeavour to answer these questions. In ordinary cases of debility there is no doubt feeble breath-motion, as there is feebleness of every other vital act, and there are also many healthy persons in whom the breath-motion and breath sounds are less strong than is found in the majority of cases. Yet, to an ear well trained to this enquiry, there is no difficulty in the diagnosis, for the degree of feebleness is far less than is found in that stage which immediately precedes tubercle, and in all cases of mere debility the vesicular sounds and the trajet of the air become normal in deep inspirations. This latter we hold to be the true diagnostic sign; and although the state of the ordinary respiration is often a sufficient guide, it is better for every observer, whether peculiarly trained or otherwise, to examine the condition in forced inspiration also. In practising the latter examination, it is highly important that the inspirations be not made in a rapid and jerking manner, but with ease, regularity, and moderate force, for in all conditions of the lungs in which the inspiratory effort is very forcible and