90 VKTICRINARV ]'A'ril(ll,ll<;Y. 



tive. The result <if the union with, or action of, the toxin toxo- 

 phore upon a cell ma_y produce immediate destruction of the 

 cell or it n:ay stimulate the cell to produce more receptors. The 

 presence of toxin in the body fluids stimulates the bod}' cells 

 to produce receptors in excess. The increased receptors may 

 remain in connection \\-ilh the central biidy or the}- may become 

 detached and float in the body fluids. Free receptors in blood 

 serum is the essential acti\-e j)rinci|)le of antitoxin. To.xic im- 

 munii}- may be better understood by givinp;- an example. 



Example. — Tetanus is an inti ixication disease due to the pro- 

 ductirm I if to.xins b\' localized bacterial actiyity uf the tetanus 

 liacillus. Inuuunit\- tn tetanus is dependent upon the neutraliza- 

 tiim I if the tetanus toxin. The tetanus toxin is composed of hap- 

 tophores and trjxophorcs. The body cells possess receptors calla- 

 ble of union with the tetanus toxin haptophores. The union of 

 cell receptors and tetanus toxin hapto])hores enables the tetanus 

 to.xin toxiiph(-ire to act upon the central mass of the b(jdv cell, 

 thus stimulating them to form more receptors. The excess recep- 

 tors become detached and float free in the body fluids and com- 

 bine with the tetanus toxin hapto])hore, thus preyenting the lat- 

 ter from com1)ining with the attached cell receptors. The te- 

 tanus toxophores are not ca])a1)le of combining with the central 

 mass of the body cells e.xcept through the medium of tetanus 

 toxin haptophores and if the tetanus toxin liaptaphores are 

 locked up \\'ith the detached cell rece])tors, the tetanus toxo- 

 phores remain inacti\-e and the animal is not inconvenienced by 

 their presence and is inunune. 



Toxic immunity is therefore dependent upon first, sufficient 

 free receptors to lock up the haptophores thus inhibiting the 

 action of the toxophore or second, upon the absence of hapto- 

 phores. 



Bacterial iniiininity. — l-"roi?T the ])henomena obseryed in Pfeif- 

 fer's reaction kihrlich has jiroposed an h\'])othesis in explanation 

 of liacterial immunity. As jjreviousK' stated, normal blood serum 

 contains fjacteriolytic substances (see humoral thcor}-). Comple- 

 ments are destroyed bv a temf)erature of .")."i°C. The blood serum 

 of immune animals possess another substance, in addition to 

 complement, not destro3'ed, by heating to ~)^>°C. These are called 

 amijriceptors. According to Ehrlich. amboeeptors, like toxins, 

 are composed of two dififerent comljining groups, also designated 

 haptophores and toxophores. The coniplemental substance of 

 normal serum is not capable of action upon bacteria. The ambo- 

 ceptor haptophore has an affinity for the convfiiement of normal 

 serum. The amboceptor toxophore has an affinity only for bac-- 



