VIII, B, 2 Hilario: Tumors of Pituitary Gland 103 



grayish bands which cross through the mass in different directions. By 

 the side of the tumor passes the optic nerve which is more or less com- 

 pressed as well as the left olfactory bulb, and probably also the optic 

 chiasm. The third or oculomotor nerve appears to be intact. The base 

 of the encephalon is considerably compressed by the larger lobe of the 

 tumor, above which there is a well pronounced depression in the cerebral 

 substance. Also the base of the left frontal lobe appears so flattened 

 from behind forward that its anteroposterior diameter has been reduced 

 to half its normal size. The same compression is exercised over the 

 temporal lobes, increasing the distance between the two. 



The cranium with the exception of a few small cavities, irregularly 

 marginated, in the enlarged sella turcica, does not show any other 

 anomaly of importance. 



Microscopical examination of the tumor. — The tissue was fixed and 

 stained by the method of Mallory for the neuroglia (phosphotungstic acid 

 and haematoxylin stain) and by the ordinary procedures of staining with 

 eosin and haematoxylin. 



On the surface of the section there is a band of fibrous connective 

 tissue which represents the capsule. Immediately within this there is 

 a zone of cells, more or less closely packed, with round bluish nuclei 

 and a moderate quantity of protoplasm which possesses a certain affinity 

 for eosin, with outline more polygonal than circular, although there are 

 some few of the latter type. Interposed between these cells are some 

 rather pale-red globules. Sometimes these cells group themselves around 

 spaces more or less oval, simulating blood vessels loaded with red globules. 

 Some fusiform, long, delicate cells are insinuated between the groups 

 of cells. 



The subjacent zone is composed of cells of almost the same size as 

 the preceding, with round nuclei, less dark, and with a small quantity 

 of transparent protoplasm, in whose periphery are projections of radiat- 

 ing apophyses which give to the cell a stellate shape. These appendices 

 appear to be connected with one another, but there are some free and 

 isolated. One can find, irregularly distributed, some spaces more or 

 less irregular, without a definite wall, and surrounded by one or two 

 rows, often interrupted, of cubical cells so similar to the stellate cells in 

 size that it is difficult to establish an exact distinction owing lo the 

 close packing of the former. Within these spaces there seems to be 

 some homogeneous rosy substance. Inserted between these are found 

 spaces without evident walls, as a mechanical effect of mere separation 

 of the cells to give access to a group of red globules which, densely 

 packed in the cavity, spread themselves among the stellate cells of the 

 periphery. 



The innermost or deepest zone offers a more I'emarkable aspect. Islets 

 are seen, generally connected with one another, isolated occasionally, 

 made up entirely of stellate cells identical with those of the anterior 

 zone; between these islets there are spaces which, insinuating themselves 

 between the cell masses, distribute the blood to all parts of the zone. 

 These extensive spaces lack walls, and their borders are simply limited 

 by the peripheral cells of the islets. Within the latter there are leuco- 

 cytes, probably of a migratory character as they are few in number. 



Scattered between the last two zones are found stellate cells disposed 

 around a more or less oval space, apparently without lining, but examin- 



