36 



THE ALUMNI JOURNAL. 



The introduction of chlorine in the 

 molecule of a hydrocarbon imparts a toxic 

 effect increasing with the number of chlo- 

 rine atoms, thus we have — ■ 



Mon-chlor-methane— CH3CI 



Methyl chloride. 

 Di-chlor-methane — C H.CL 



Methylene chloride. 

 Tri-chlor- methane— CH CI3 



Chloroform. 

 Tetra chlor-methane— C CI4 



Carbon-tetrachloride. 

 Again the introduction or substitution of 

 methyl groups, under certain conditions 

 causes a marked neutralization of the 

 toxic effect of a body in question, thus the 

 hypnotic action of sulfonal is greatly 

 lessened by the substitution of methyl 

 for ethyl groups. Xanthin, caffeine and 

 theobromine are homologues, the tetanic 

 effects exhibited by xanthin (CaH.N^Oo) 

 are tound only in a greatly reduced degree 

 in its methyl derivatives caffeine (C5H 

 (CH3)3N4 02) and theobromine (C5 H, 

 (CH3)oN^02). Similar relationship ex- 

 ists between strychnin and brucin. The 

 tertiary united carbon as in 



Pental ^i"'>C:^-C<^.''\ or 



Amylene-hydrate ph'-^^'^OH ' °^ 



Sulfonal CH >^^S0!-C h' '^ b'P^otic. 



As we will later see, that slight altera- 

 tions in the structure of these bodies, 

 such as the introduction of new groups, 

 preparation of homologues, produce 

 marked differences in physiological 

 action. A careful studj^ of this feature 

 applied to a large number of synthetic 

 compounds has demonstrated that certain 

 normals, in the configuration of the con- 

 stitution of certain bodies, occur with 

 regularity in antipyretics, hypnotics and 

 other remedies. 



In this study progress is rendered slow 



and difficult, and if all conditions are not 

 carefully considered, erroneous results 

 may be obtained ; thus substances which 

 persistently resist the action of reagents 

 in the laboratory, readily break up under 

 the influence of the vital processes in the 

 organism, while the reverse is true of 

 readily decomposable substance's, these 

 undergoing no change in the system. 

 Again many bodies react contrary to 

 expectations, because they undergo un- 

 expected changes in the organism, be- 

 coming altered before performing the 

 action desired. Solubility plays also a 

 very important roll. We also find singu- 

 lar contradictions, as instances of this, 

 antifebrin and antipyrin, remedies having 

 no chemical relationship to one another, 

 produce similar effects on the animal 

 organism. 



Again on the other hand, bodies which 

 are chemically closely related, are found 

 to possess widely different physiological 

 action, for instance red phosphorus is 

 non-toxic, while the yellow is the reverse. 

 Among the oxy-benzoic acids, the 7neta 

 and para acids have no medicinal action, 

 while ortho compound forms the valuable 

 salicylic acid. Thus while the mono- 

 hydroxy-benzene (phenol CgHsOH) and 

 amido-benzene (anilin CeHjNH.,) are pois- 

 onous, the para-amido-phenol 



(CeHj<C^TT ) which contains both 



groups, is relatively non-to^ic. Ethylated 

 and acetylatedp-amido-phenol, (phenace- 

 tin) is antipyretic. Many other inex- 

 plainable examples might be given, this 

 however, should not deter our attention 

 from a most important subject, even 

 though we are not at present, able to 

 offer satisfactory explanations for these 

 apparent contradictions to the theory. 



On the other hand, we have striking 

 examples which serve to prove that there 

 must be a definite relationship between 

 chemical constitution and medicinal 



