426 The Philippine Journal of Science uu 



2. A theory based upon the latent valency of this acid has been 

 advanced to account for the remarkable changes it produces in 

 these spectra. 



3. This theory includes the color of phthalids and phthaleins 

 dissolved in sulphuric acid and of the thio derivatives of this type 

 of compounds. 



4. The counterinfluence of substituting nitrogen in the side 

 chain is discussed in relation to its effect on absorption spectra. 



