Ehrlich's Theory of I in in unity. 23 



"side-chains'' the various atoms or groups of atoms linked 

 about this nucleus, so in Ehrlich's view the living proto- 

 plasmic molecule may be thought of as having as its elemental or 

 basic compound a vital nucleus about which are attached, and 

 probably from which spring, a number of other atomic groups 

 subsidiary to the center of the molecule and corresponding to the 

 side-chains of the formula, but essential to the efficiency and 

 integrity of the whole complex molecule, since they are its means 

 of combination. These are the receptors or haptophores of the 

 molecule. Every molecule possesses these haptophores in addition 

 to its principal part, the centre or nucleus (in living protoplasmic 

 molecules, the vital centre). Should these haptophores be lost in 

 the living molecule, they are replaceable by others of like type 

 because of the vital regenerative power of the molecule.] 



The receptors are the principal instruments of [molecular, or 

 in other words] intracellular metabolism and provide nutri- 

 tive substance to the cells through their ability to unite chemic- 

 ally with such material. However, just as proper food elements 

 may thus combine, so other albuminous bodies or materials chem- 

 ically allied to foods become linked to or combined with the 

 receptors, as material extracted from bacteria, various poisons 

 of animal, bacterial and vegetable origin (toxines, venom of bees, 

 spiders or snakes, diphtheria toxine, ricin, abrin, the substance 

 of blood cells, spermatozoa and nervous tissue, and the milk 

 albumen of different kinds of animals). Such union occurs be- 

 cause these substances contain in their molecular composition 

 certain groups of atoms, which, like similar atomic groups in 

 foods, have an affinity (chemical affinity) for the atomic groups 

 of the cellular protoplasm ; these Ehrlich speaks of as their 

 haptophore groups. [Thus both the protoplasmic molecules of 

 the body cells are provided with haptophores or combining chains, 

 and, too, all nutritive or harmful molecules which come in con- 

 tact with them. Should there be affinity between the haptophores 

 of the cellular protoplasm and those of the introduced molecules a 

 combination will result.] With such combination effected 

 [the molecule and in proportionate degree the whole] cell comes 

 under the influence of the substance chained to it. Should 

 the latter possess properties actively harmful to the protoplasm, 

 poisonous qualities (toxophorc) , the cellular protoplasm becomes 

 more or less injured, and a pathological cellular lesion results. 

 There may ensue complete death of the cell [protoplasm], 



