ACTIN0MYK08IS. 
59 
The round or somewhat oval-shaped tubercles were generally 
about 0.45 mm., seldomer 0.30 ; 0.27, or 0.20 mm. in diameter,* 
and contained either a dark-tinted nucleus, or a spongy structure, 
with perhaps a dark nucleus in its midst. 
This dark nucleus proved to be the most interesting discovery 
in the diseased lung. It was a round, globular, rarely a slightly 
oval body, with a diameter of from 0.04 to 0.05 millimeters. 
Under a low power its contour was sharp and distinct, and it had 
a yellowish-green tint, with a markedly radiating structure. With 
a higher radiating power, the contour was no longer sharp and 
circular, but notched or indented irregularly, and the radiating 
lines were found to be minute club-shaped particles, the smaller 
extremity being at the centre and the wider part toward the per¬ 
iphery of the mass. Still more highly magnified, there were 
distinctly observed in these radiating parts, particularly toward 
the centre, exceedingly minute, structureless granules of a light 
yellowish-green tint, refrangent, of a diameter between 0.008 to 
0.01 mm. 
In some of the tubercles it was very difficult to discover this 
radiating nucleus; it was so small and delicate that it had to be 
looked for with the greatest care and patience, and was often 
composed of only a small number of the club-shaped radiating 
portions—from four to six, or only three, starting from a point in 
the centre. 
In each tubercle, around the fungus, and forming a medium 
stratum, was a large mass of cells, about 0.25 mm. in diameter. 
These cells were round or slightly polygonal, and lying close to 
each other. There were also spindle-shaped and other cells. The 
cells of the middle stratum were composed of faintly granular 
protoplasm, with a large nucleus, which was stained a deep blue by 
hasmatoxylin. The external stratum was fibrous, the fibres be¬ 
ing concentric around the cells; it formed the limit of the tuber¬ 
cle, isolating it more or less from the normal inter-alveolar tissue. 
* A very large tubercle gave the following dimensions: Total diameter, 1.00 
mm.; thickness of fibrous portion, 0.20; the middle cell portion enclosing the 
fungus, 0.60; Actinomycet tufts, 0.15. 
