ally superadded to those of the first, and are developed out of the greater intensity acquired by the disease; not only do we observe the introduction of new symptoms, but those pre-existing in the first stage acquire a much greater intensity. Consequently the debility of the patient, the loss of nervous energy, and the muscular prostration are greatly increased. The vision grows dimmer, the local anesthesia deepens, and the sleeplessness at night becomes more and more distressing.

The symptoms which now become engrafted on the preceding are: intense thirst, a dry parched skin, a greatly increased appetite, increasing emaciation, which ultimately becomes extreme, and an excessive flow of urine of high specific gravity and strongly impregnated with sugar. These are the symptoms of the disease when it is fully developed, and they gradually increase in intensity until near its fatal termination. It is necessary that they

should be considered somewhat in detail.

Thirst, or polydipsia, is a symptom always present in this stage, in greater or less intensity according to the quality of the diet of the patient and the severity of the disease (two circumstances which chiefly determine the amount of sugar present in the blood), or, in other words, the intensity of the

or

glycaemia. The existence of thirst at this period, and increasing in urgency as the malady advances, is not difficult of explanation. We know that in the process of osmosis through membranes very different quantities of water are attracted absorbed by different substances. Water is the endosmotic equivalent of sugar by which it is attracted and absorbed in large quantities from the blood and extra-vascular fluids in diabetes, and afterwards carried out of the system with it by the kidneys; hence the excessive flow of saccharine urine. But the continuous unceasing withdrawal of such large quantities of water from the blood and tissues. excites a proportionate degree of thirst, in accordance with a physiological law, to replace the deficiency thus produced. It follows, therefore, that the thirst and polyuria must necessarily bear a direct ratio to each other and that both originate from the same cause, namely: a peculiar physical property of sugar and a well-known physical law which it sets in operation in the blood.

It is the persistent thirst, accompanied by a persistently copious discharge of urine, which generally first excites in the minds of the patients and their relatives a suspicion of diabetes when the disease has not been detected before these symptoms become

urgent. The thirst is generally most intense towards evening and at night, and, with the parched mouth and sleeplessness then present, renders the condition of the sufferer exceedingly wretched and distressing. The quantity of water consumed daily by diabetics is frequently enormous, and the thirst is never appeased; it varies in different individuals and in the same patient at different periods, so that no correct estimate of it can be formed. In my own experience I have known it exceed thirty-six pints or four and a half gallons in the twenty-four hours; but other observers have recorded the drinking of much larger quantities.

A dry, parched mouth is another distressing phenomenon associated with the intense thirst, and not assuaged by the frequent large draughts of water taken by the patient; the dry tongue cleaves to the mouth, and the lips are also dry and parched.

A dry and unperspiring skin is an almost constant symptom in this stage of the disease, and, like the thirst, is produced by the continual abstraction from the system of the large quantity of water which passes off by the kidneys as urine. Dr. Prout1 records that he has seen cases in which this symptom was absent, and in which perspiration and even 1 Op. cit. p. 29.

sweating was produced by slight exercise; but notwithstanding such exceptional cases, this symptom is very generally present and much complained of by the patient. The insensible perspiration is enormously diminished, so much so, that according to the experiments of Von Dursch' only 200 grammes of water passed off by the skin and lungs in the 24 hours, instead of the normal quantity escaping through these channels, namely: 1,000 or 2,000 grammes. Probably the whole of the small quantity stated by Von Dursch escaped by the lungs.

Polyphagia, or inordinate appetite, is not as a rule prominently developed until the second stage is considerably advanced and the period of emaciation has set in; it indicates the advent of the most serious phase of the disease, when a considerable portion of the albuminoid principles of the food is . converted into sugar and eliminated by the urine. It follows, therefore, that the intensity of the polyphagia is an unerring index of the extent of the mal-assimilation and saccharine metamorphosis of the nitrogenous alimentary substances destined for the healthy nutrition of the tissues of the body. This misappropriation of the food of the tissues creates a corresponding want, which in its turn

Quoted by Dr. Parkes, On the Urine, p. 339.

excites an inordinate appetite; hence the origin of the symptom. It is needless to observe that the polyphagia increases in intensity with the further progress and increased severity of the malady; so that even enormous quantities of food are consumed by the patient without the cravings of hunger being satisfied. Under these circumstances it is exceedingly fortunate that the function of digestion is generally vigorous and unimpaired, so that quantities of food are digested which in the healthy subject would produce serious gastric disorder.

Emaciation, gradually progressive and ultimately extreme, is a constant and exceedingly prominent symptom of the disease when it has reached the second stage, and it is one moreover which has attracted the attention of physicians from the earliest period of its history. Indeed, so extreme does the emaciation become when the malady runs its course uninterruptedly to a fatal termination and life is not cut short by the invasion of some other incidental affection, that the patient becomes ultimately reduced to a mere skeleton.

The exact period at which the emaciation begins is subject to considerable variation in individual cases, being regulated in this respect by the intensity of the disease and other conditions. The first stage