1906.] Specificity and Action in Vitro of Gastrotoxin. 433 



those in the salt solution, as the latter tend to stick together by reason of the 

 mucus, which it is impossible to clear away completely. 



The cells in the salt solution are quite normal in appearance, but the cells 

 which have been exposed to the action of the gastrotoxic serum have 

 become more or less hyaline. 



The oxyntic cells are not so much affected as the central cells, the masses 

 of which appear like pieces of floating glass. The granules are obscured, 

 and many of the cells look like shadows. The nuclei can usually be seen 

 except when the cells are massed together. 



The cells are examined in the fresh state, as this seems to me to be the 

 best for practical purposes. I have also stained them with watery solutions 

 of methyl green, picrocarmine, and safranin, but this does not materially 

 assist. The stained cells which are affected look like pieces of coloured 

 glass. 



This effect of the gastrotoxic serum appears later than those described 

 above, and is not observed until after the expiration of about five weeks 

 after the first injection, four or five injections having been given in the 

 meanwhile. The effect begins to pass off between three and four months 

 after the first injection, the animal receiving injections at regular intervals. 



The serum of a normal rabbit differs in no respect in its behaviour towards 

 the gastric cells from salt solution. 



Effects of Heat. — A temperature of 55° C. maintained for half an hour 

 does not destroy the action of the serum upon the gastric cells. It may be 

 weakened, but only to a slight degree. This result points to the conclusion 

 that a complement exists in the cells themselves, if the action is due to a 

 cytolysin of the same construction as a hamiolysin. Such endocellular 

 complements have of course been described before. 



I have heated the stomach to 55° C. for half an hour before obtaining the 

 cells, and have found that in this case the serum produces no effect upon 

 them. This experiment of course proves nothing, because it is probable that 

 the vitality of the cells is destroyed by exposure to this temperature, since 

 cell globulin coagulates at 48° to 50° C. 



Removal of Gastrolytic Factor. — By saturating the serum with washed 

 gastric cells of the guinea-pig and allowing the mixture to stand for one hour, 

 the gastrolytic factor is removed and the action of the serum upon the cells is 

 destroyed. Xo change is visible in the cells which have been used to saturate 

 the serum in the space of one hour, and, since they remove the gastrolysin, it 

 is evident that the latter becomes anchored to the gastric cells preparatory 

 to acting upon them. This brings the gastrolysin into line with a heemolysin 

 in this respect. 



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