Makch 27, 1914] 



SCIENCE 



447 



No. 15 



OH 



I 1 I 



NaOsS SOaNa 



It is apparent then from the foregoing 

 that if the alpha-naphtol receptor is to 

 work, it can only do so in the presence of 

 two sulfonic acid groups. 



When, now, we examine the behavior of 

 the beta-naphtol sulfonic acids in this re- 

 spect, we find that, strangely enough, one 

 of the monosulfonic acids (namely the 2.8 

 acid) produces a dye which acts as a vital 

 stain.^ 



No. 237 



NaOsS N = N< 



>N 



III I I 



The other mono acids which we have ex- 

 amined (the 2.6 and 2.7 acids) produce 

 entirely negative dyes. 

 No. 26 



n = n/ 



I I 



]0H CH3 



\/\/' 



■SOsNa 



<: 



>0H CHs CHs HO 



NaOaSi 

 No. 27 



Whereas of the disulfonic acids, the 2.3.7 

 and 2.6.8 acids produce dyes which arenon- 

 stainers, the 2.3.6 acid combined with toli- 

 dine furnishes a dye which approaches a 

 true vital stain. 

 No. 236 



-<:x:> 



NaOaSl 



iSOsNa 



NaOaS 



SOaNa 



2 The dye was made for us by Dr. 

 through the kindness of Sehaellkopf, Hartford and 

 Hanna, Buffalo. 



X X> - 



OH CHs CHa HOf 



\n = N 



A comparison of the different effects se- 

 cured by the two dyes 236 and 237 is inter- 

 esting, for it is difficult to believe that the 

 exact position which the sulfonic acid 

 radicle assumes in the naphthaline ring is 

 an adequate explanation of this. In all the 

 dyes which we have examined, the number 

 of sulfonic groups has been important, but 

 not the position which they occupy. The 

 precise point of insertion in the naphthaline 

 ring was of little moment and we have to 

 inquire in dyes 236 and 237 why the shift- 

 ing of one SOgNa group from 6 to 7 changes 

 a positive into a negative dye. Now 

 these two isomeric acids, apart from their 

 close chemical relationship, have long been 

 known to produce dyes which differ 

 greatly in some of their non-chemical char- 

 acteristics — characteristics which we be- 

 lieve determine whether a dye of the benzi- 

 dine class shall be a vital stain or not. 



For the present, however, let us believe 

 that there is a general alpha-naphtol-disul- 

 fonic eeptor, a particular beta-naphtol-di- 

 sulfonie eeptor (viz., the 236 one) and a 

 particular beta-naphtol-monosulfonic eep- 

 tor (the 28 one) whereas none of the other 

 monosulfonic and none of the other beta 

 disulfonic acids have chemoceptors corre- 

 sponding to them in the cell. 



When we consider the dyes made from 

 the naphtylamines we must still further 

 extend our list of hypothetical chemocep- 

 tors, for many of these dyes are brilliant 

 vital stains, among them 13, 15, 16, 26, 27 

 and 28. 



