The "Lateral-chain Theory" of Immunity 117 



have additional functions that are special and somatic. As examples 

 of the first, nutrition and reproduction may be suggested, of the 

 second glandular secretion, nervous impulse transmission, muscular 

 contraction, bone and pigment formation. 



The nutrition of each cell in a composite organism, therefore, re- 

 quires material with which to meet two demands, first the sustenance 

 of its own substance, second the supply of those special or particular 

 substances through which its special functions are to be performed. 



According to its particular necessities each cell is undoubtedly 

 endowed with selective affinities by which these appropriate sub- 

 stances are caught, held and brought finally into molecular composi- 

 tion with the cell substance. This is, naturally, a chemical problem, 

 but one of such complexity that no symbols used in chemical science 

 enable us to follow it either accurately or adequately. 



To arrive at a clear comprehension of the matter, and to progress 

 from this comparatively simple beginning to the more involved 

 problems to come later, conventional chemical expressions and sym- 

 bols are laid aside, and new and simple symbols introduced. 



The cell is conceived to consist of an executive center (Leistenkern) 

 surrounded hy numerous conductors (Seitenketten) or "side-chains." 

 It is by the latter that molecules brought to the cell by the inter- 

 cellular lymph are caught and held when of a quality necessary to 

 the requirements of the cell and of a composition adapted to one or 

 more of the side-chains. 



The side-chains are known as receptors or haptophiles {awTtiv 

 to bind and c^tXetj' to love). A chemist is apt to picture to himself 

 a benzine ring with its various possibilities of combination and sub- 

 stitution, but, as has been said it seems better to avoid this form 

 of symbol. Ehrhch pictures . the cell as a sphere the surface of which 

 is covered by nipple-like processes, the receptors. 



The molecules in the body fluids are conceived to be or not to be 

 provided with adaptations to these receptors, according to their 

 nature. The adaptations go by the name of haptophores (arreu', to 

 bind and <j)ipeiv, to bear) and are graphically represented as small 

 figures, excavated at one end so as to fit on the receptors. Under 

 normal conditions during which cell nutrition and cell function 

 progress regularly one conceives that useful molecular groups with 

 haptophores adapted to the receptors are constantly brought to the 

 cell, and are seized and held until incorporated into the composition 

 of the cell itself. 



Under abnormal conditions, however, new substances appear in 

 the tissue fluids, among which are toxic products of micro-organis- 

 mal metabolism, should these have haptophores adopted to the re- 

 ceptors of the cell, they may be caught and held with disastrous 

 results for if they are in sufficient number to immediately appropriate 

 all of the receptors so as to exclude the necessary molecules, and be 

 of themselves of no nutritive value, the cells may die of starvation- 



