Page:A Handbook of the Theory and Practice of Medicine - Volume I - Frederick T. Roberts.djvu/81

 FATTY DEGENERATION.

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I. Fatty Metamorphosis.— The fact of the direct conversion ot the albuminoid constituents of tissues into fat has been established by observation and experiment, and it is a frequent pathological occurrence, being- one of the natural events of decay in old age, when it often leads to serious consequences. The process may take place in connection with cells or fibres. The fat is usually deposited in a gra- nular form, but ultimately it may accumulate into masses or run into drops of oil. The granules are recognized by their dark and distinct outline ; their peculiar refractive power upon light; and their solubility in ether. Fatty metamorphosis can be best studied by a description of the process as observed in certain individual tissues.

Muscular tissue. — Voluntary muscles may become the seat of fatty change, of which a striking exam- ple has come under mv notice, where almost the whole of the muscles of the thigh on one side were Fatt7 degeneration of converted into fat, without any alteration in their fi^i^es of stnped muscle, general size or shape, or m the arrangement of their fibres. The subject, an old woman, had been bed-ridden for several years. It is in the fibres of the heart, however, that this degeneration is most commonly observed. Under the microscope these fibres are seen in the early stage to be somewhat dim as re- gards their transverse striae, owing to the presence of a few minute fat-granules, arranged either in transverse or longitudinal lines, or in an irregular manner. Ether dissolves the fat and brings the striae again into view. The increase in the number and size of the granules causes them to become more and more obscure, until eventually every trace of muscular fibre disappears, and its place is occupied by fat molecules and oil drops. Where sarcolemma exists this may ultimately rupture, and the fat becomes scattered about. The cells of involuntary muscular tissue are also liable to undergo fatty change, granules gradually filling them up and concealing their nucleus, complete destruction finally ensuing. The conversion of muscle into adipocere after death is_a form of fatty degeneration.

Blood-vessels. — The arteries are very prone to fatty degeneration as age advances, the process either starting as an immediate change in the cells of the inner coat or in the muscular coat, or being associated with the condition named alhcroma. At last the tissues may be more or less destroyed and carried away by the blood-current, leaving uneven erosions on the inner surface of the vessels. The capillaries are also apt to undergo a fatty change.

The nerve- tissues, both cells and fibres, are subject to fatty degen- eration, becoming the seat of much molecular fat, and finally breaking down. This is well seen in softening of the brain or spinal cord.

The following may be mentioned in further illustration of fatty degeneration in cells. The so-called "compound inflammatory

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