io8 ROMER'S EXPERIMENTS 



Dmitrevsky are also of great interest, and almost constitute a 

 crucial experiment. 



If Ehrlich's theory is true, and if antitoxin is produced by the 

 budding-off of the receptors in great numbers, it ought to follow 

 that the brain of an immunized animal, which contains these 

 receptors in abnormally great amount, ought to have a greater power 

 of neutralizing toxin than that of normal animals. But Dmitrev- 

 sky's experiments show that this is not the case, and constitute a 

 strong proof against the theory in its original form. It seems fair 

 to conclude that Wassermann's phenomenon is due to some 

 accidental property of the central nervous system, or possibly to 

 the presence of fats, and must not be quoted as evidence of the 

 origin of antitoxin from the cells on which it chiefly acts. 



Romer's experiment was made with abrin, a substance which 

 has the power of causing violent conjunctivitis. He made use 

 of rabbits, instilling small but increasing amounts into the right 

 conjunctiva. After three weeks the animal was killed, and each 

 conjunctiva dissected off, ground up with one lethal dose of abrin, 

 and injected into animals. The right conjunctiva, that into which 

 the abrin had been instilled, was found to act as an antitoxin and 

 to neutralize the abrin, whereas the left was devoid of this power. 

 Of course, if the process were carried on for a long time the abrin 

 would be absorbed into the system, and there would be a general 

 production of antitoxin, but at first the process appears local. 



These researches are interesting, but do not seem to have any very 

 direct bearing on the question at issue. They show what does 

 not require proof that tissues which are not reached by the toxin 

 do not produce antitoxin ; but the question as to whether the 

 latter substance is produced by the cells which are peculiarly 

 susceptible to the toxin is not elucidated. There are in the 

 conjunctiva numerous structures connective-tissue cells, blood- 

 vessels, endothelium, epithelium, leucocytes, etc. and these 

 experiments afford no means of gauging which of these are 

 affected by the toxin or which produce antitoxin. The behaviour 

 of the leucocytes is of especial interest ; they are present in the 

 inflamed conjunctiva in increased amounts, and the question may 

 be asked whether the apparent antitoxic action of the right con- 

 junctiva may not be due to these cells, which are present in but 

 small numbers in the left. This view is rendered more probable 

 from the further researches of Romer, who showed that in 

 immunized animals antiabrin is present in greater amounts in the 



