10 Elirlich's Theory 



after each toxin injection, the fall in antitoxin being followed in due 

 course by a rise to a point higher than before. Salomonsen and Madsen 

 (IV. 1897, p. 326) also observed this in horses treated with diphtheria 

 toxin. The antitoxin content of the serum or milk always fell after a 

 fresh toxin injection, gradually rising afterwards, the maximum amount 

 being usually reached 9 -10 days after the last toxin injection. A 

 similar observation has been made with regard to the precipitins, and 

 the phenomenon will probably be observable in relation to all antibodies. 

 (See Appendix, Note 1.) The decrease of antitoxin appears to denote 

 that the toxin and antitoxin are combining in corpore. 



The question of the regeneration of antitoxins in corpore has 

 been the subject of some investigation. Thus Roux and Vaillard 

 (ll. 1893, p. 82) found that they could remove (by repeated bleedings 

 in a few days) as much blood from a tetanus-immune rabbit as the 

 animal originally possessed, but the newly-formed blood was apparently 

 as antitoxic as that removed at first. Salomonsen and Madsen (XI. 

 1898, p. 763) made similar observations with regard to diphtheria! 

 antitoxin in the serum of goats and horses, the animals being in a 

 condition of antitoxic equilibrium. These observations, as also the fact 

 recorded by the last authors mentioned (Gompt. rend. Acad. des Sc., 

 Paris, 1898) that the administration of pilocarpine increased the amount 

 of antitoxin present in the serum of immimified animals, have been 

 brought forward in evidence as to the secretive nature of the anti- 

 bodies. 



It has been claimed that normal antitoxins are present in the serum 

 of animals. Thus Meade Bolton, in Philadelphia, and Cobbett, in Cam- 

 bridge, found a certain percentage of normal horse sera to possess slight 

 but distinct antitoxic properties for diphtheria toxin. Cobbett has 

 however recently had occasion to observe diphtheria in the horse 1 . Con- 

 sequently a doubt arises as to the former observation bringing strict 

 evidence as to the existence of normal antitoxins. On the other hand 

 their existence can scarcely be doubted for the reason that substances 

 fulfilling the function of different antibodies have frequently been 

 noticed in normal sera. Quite recently, moreover, von Dungern (1902, 

 p. 37) has observed that rabbit serum contained a " normal antitoxin " 

 for the toxin contained in the eggs of starfish (Asterias glacialis, and 

 Astropecten aurantiacus), the toxin in question acting upon the sperma- 

 tozoa of sea-urchins. 



1 Cobbett, C. L. (1900), Diphtheria occurring spontaneously in the horse, Lancet, vol. n. 

 p. 573. 



