1904.] Production of a Specific G-astrotoxic Scrum. 139 



were killed on the following day, post-mortem lesions being thus 

 absolutely excluded. 



The areas of necrosis appear in the form of black patches, round or 

 irregular in shape, from the size of a pin's head to a large area, 

 occupying a third or more of the surface of the stomach, and contrasting 

 markedly with the surrounding mucous membrane which is normal. 

 The black colour is due to altered blood pigment, a variable amount of 

 which is usually found clinging with particles of food to the necrosed 

 patches, from which it can be washed off, leaving the blackened and 

 necrosed tissue plainly visible. This altered blood is present in very 

 variable amount, sometimes being in considerable quantity, at other 

 times scanty, with the necrosis greatly in excess. 



The patches are found most commonly near or on one of the 

 curvatures, but they may occur anywhere in the stomach. Their usual 

 situation on the curvatures may be due to the fact that the main blood- 

 vessels of the stomach run along the latter, and, therefore, these parts 

 are the first to be exposed to the action of the toxin. Sometimes, also, 

 the patches spread out into streaks, passing along the anterior and 

 posterior walls of the stomach from the curvatures, as if they followed 

 the distribution of the blood-vessels. In some places the necrosed tissue 

 has disappeared, leaving ulcers with blackened edges and bases. After 

 about 48 hours the black tissue apparently disappears, leaving a 

 perfectly clean and sharply punched out ulcer. 



Microscopic Appearance. The necrosed patches are sharply marked 

 off from the normal tissue, and do not extend beyond the muscularis 

 mucosse, the muscular coats and peritoneum being normal. 



The cells of the glands in the necrosed patch, when they can be 

 distinguished, are seen to be diffusely and very faintly stained by the 

 eosin, their outlines are clouded, and they look shrunken ; the nuclei 

 are not stained, although towards the margin of the patch they can just 

 be distinguished. 



In a small patch, which is apparently just commencing, the cells, both 

 oxyntic and central, have the above appearances, whilst the interstitial 

 connective tissue cells take the stain well, and show up by contrast. In 

 a farther advanced stage the whole patch is diffusely stained a faint 

 pink colour or totally unstained, and the gland cells are irregularly 

 arranged more or less in columns, but no definite idea of what structure 

 had preceded this patch can be made out. A certain amount of 

 altered blood pigment in the form of scattered brownish granules 

 can be seen, but, as a rule, the necrosed tissue is singularly free from 

 blood. 



Towards the edge of the patch the normal tissue contains a few 

 necrosed cells, and the edges and base are infiltrated with leucocytes. 

 In many sections the bases of the glands do not appear to be so 

 disintegrated as the inner ends. Sometimes the patch looks like a 



