Microincineration of Tubercles

Abstract

The technic of microincineration as developed by Policard 1 and modified by Scott 2 has been used in studying the mineral content of tubercles from human tuberculosis and experimental tuberculosis in guinea pigs. Alternate serial paraffin sections were stained and ashed. The ashing process was carried out in a muffle furnace at a temperature of approximately 540°, about 4 hours being allowed for the incineration.

The general observation made by previous investigators that the nucleus is the part of the cell richest in ash, was confirmed. The distinction was found to be conspicuous in the tuberculous spleen, where the mineral-rich Malpighian corpuscles stood out sharply against a mineral-poor background, the latter being found by comparison with the stained sections to consist of aggregations of epithelioid cells. In general the epithelioid cell cytoplasm was found low in ash.

As a rule regions of degeneration and recent necrosis were found to contain less ash than the corresponding undegenerated tissue. This was the case in guinea pig tubercles, acute tuberculous pneumonia in man and chronic fibrocaseous human tuberculosis. A peribronchial tubercle (guinea pig) in the corresponding stained and ashed sections is shown in the accompanying figure (Fig. 1). It will be noted that the center of the ashed tubercle contains somewhat less mineral than the outer zones, and that this region corresponds to a spot of early degeneration in the stained tubercle. It seems reasonable to attribute the loss of mineral to karyolysis and diffusion away of soluble mineral material.

In later stages of the human disease remineralization of necrotic tissue could be observed. In sections of experimental tuberculosis kindly furnished by Dr. Spies, taken from tuberculous rabbits given intensive oral treatment with viosterol, the speed of this process was found to be much enhanced (compare with other results of Spies 3 ).