The specific gravity of the entire blood shows an increase to and beyond .066 and 1.068, and that of the serum up to 1.038 and 1.03-1. The lnemoglobin contents may rise heyond 10G per cent. Higher percentages, beyond 108 and 110, are doubtless due to congestive concentration. The coefficient of density at the same time will like wise indicate 100 to 105, as determined with Bizzozero's cytometer. In aummia the specific gravity sinks to 1.057-1.058 and often lower, the serum reaches at most 1.028, while the lilemoglobin contents may amount to 80 per cent. and less. The coefficient of density may fall to 70 and even less. In women all these figures are much lower, cor responding to the general proportions of their blood as compared with that of man. In plethora the specific gravity of the entire blood is at most 1.062, that of the serum 1.029, hemoglobin contents 90 per cent., coefficient of density 90-95. The lowest figures I found in anai mia were : specific gravity of the entire blood 1.050, that of the serum 1.021, hemoglobin contents 64 per cent., coefficient of density 67.8.
As compared with true plethora we find here an overfilling of the vascular apparatus with a blood which no longer possesses the normal composition, but shows more or less marked deviations as regards a diminution of its solid constituents and an increase of water.
Serous plethora develops chiefly when the excretion of the super fluous water is interfered with by disturbances of the cardiac and renal activity. Owing to the accumulation of water in the blood, de spite the existing absolute hypalbuminosis, the volume of the blood is augmented and the vascular apparatus is abnormally filled, at least temporarily until hydropic excretion occurs. Hence as a rule the contrast between the pallor of the face, of the external skin, and the mucous membranes of such persons on. the one hand, and on the other the fulness of the vascular apparatus (abnormally high ten sion of the pulse) is striking. At the autopsy of such obese per sons the internal organs are usually remarkably deficient in normally colored blood, as compared to the above-described findings in true plethora, and generally filled with only a small amount of pale, loosely coagulated blood (v. Recklinghausen).
In pronounced forms of hydrremia, according to the older obser vations, the amount of albumin in the blood is as a rule below 60 per cent. (Becquerel and Bother, Andrea and Gavaret, Abeille, C. Schmitt, and others), while the salts dissolved in the plasma remain behind with the retained water; according to C. Schmitt in the pro portion of nine parts of plasma albumin to one part of the ordinary plasma salts. The specific gravity of the entire blood, according to my observations, is in men 1.057, that of the serum 1.023, hemo globin contents 83 per cent., coefficient of density 80. In women I obtained as extreme values : specific gravity of the entire blood 1.043, that of the serum 1.019, hemoglobin contents 45-50 per cent., coeffi cient of density 56.
The in the vascular apparatus proper develop among the older corpulent persons as a rule with the symptoms of chronic endarteritis—opacity, thickening and softening of the intima with partial fatty metamorphosis of the latter; these changes may occasionally extend to the media and adventitia, and by the deposi tion of lime salts, etc., lead to the complicating diseases, sclerosis and atheroma.
In the aufemic type of corpulence, among girls, women, and young persons, the anatomical changes in the arteries are limited to the simple fatty degeneration of the intima and media peculiar to anremia, and may be often entirely absent in early age. As regards
the venous system, special mention must be made of the occurrence of varices on the legs, hemorrhoidal nodules about the rectum, vari cocele, etc., mainly in patients with plethora and in advanced age (see below).
The heart muscle, as loiig as but little fat covers it, will be able to respond to the increased demands, often even for a long time, or it hypertrophies under moderate dilatation of its cavi ties, corresponding to the greater quantity of blood, as it does in preg nancy in which it answers similar requirements.* The patient suf fers no or but inconsiderable inconveniences, perhaps only after active exertions such as running and stair-climbing, especially after a more or less ample meal when the thoracic space is at the same time dimin ished by the upward movement of the diaphragm. In some cases shortness of breath and palpitation set in after a full meal. Other symptoms on the part of the respiratory apparatus are still absent. Physical examination shows either normal conditions or at most slight enlargement of the area of cardiac dulness ; the apex beat is somewhat displaced outward, the sounds are pure, but slightly muf fled according to the more or less thick interposition of the fatty deposit.
Only when with the gradual augmentation of fat the deposit on the heart is likewise increased, especially when the fat accumu lates more and more beneath the pericardium, begins to penetrate from the sulci between the muscular layers, and the structure be comes looser, do the muscular walls distend—first the left heart by reason of the resistance in the greater arterial system and the steadily rising intracardial pressure—and a dilatation of the left ventricle re sults which leads to its hypertrophy. Since a compensation of the advancing disturbances in the circulatory apparatus is not effected thereby, or is so for a short time only, and the left heart is unable to dispose completely of the increased amount of blood which flows into it, the blood stagnates in the left auricle and dilates it, and re gurgitates and accumulates in the lungs, which in their turn increase the work of the right heart, and when the latter is unable to respond to it, a dilatation and hypertrophy of the right ventricle will be su peradded. But this lesion of the circulatory apparatus is not final. The right ventricle is less able than the left to effect compensation, and hence the congestion continues in the right auricle and the venous apparatus back of it, causing dilatation and overfilling of its vessels. It is obvious that this condition will result sooner in pro portion as the heart is unable to resist the on-flowing blood masses and the ever-increasing intracardial pressure, that is to say, the greater the deposition and penetration of the fat upon and into the muscle the more rapid the progress of the lesion. On the other hand, the resistance in the vascular apparatus by the accumulation of fat in the body, the viscera, and tissues, is increased by the fact that the fatty deposits hinder the dilatation of the arterial tube and prevent a rapid transition of the arterial systole into the diastole. The fatty de posits and the compression of the arteries therefore influence at the same time the movements of the heart and the pulse, which latter assumes the character of the pulses tardus as the heart slowly sur mounts the obstacles present in addition to the delayed expansion and contraction of the arteries.