238 Schunck . — The Chemistry 
product formed has far less characteristic and well-defined 
properties than has phyllotaonin, the analogous product from 
phyllocyanin. It may indeed be said that in every respect 
phylloxanthin is from a chemical point of view a far less 
interesting substance than phyllocyanin. Though the two 
substances so closely resemble one another, it is certain that 
they are not formed simultaneously, though they may appear 
to do so, when a strong acid, such as hydrochloric acid, is 
employed in the decomposition of chlorophyll. When a little 
acetic acid is added to an ethereal solution of chlorophyll 
there is an immediate change of colour in the solution, ac- 
companied by the formation of phylloxanthin ; it is only after 
some time that phyllocyanin makes its appearance ; at least 
such is the conclusion derived from spectroscopic examination 
of the solution. 
The close resemblance subsisting between phyllocyanin and 
phylloxanthin may be explained by supposing that they are 
derived from two distinct though nearly allied bodies. The 
researches of Stokes, Sorby, and others have led to the con- 
clusion that ordinary chlorophyll is a mixture of several 
colouring-matters, two of which Mr. Sorby has named ‘ blue 
chlorophyll ’ and ‘ yellow chlorophyll ’ respectively. In a 
written communication received from Sir G. Stokes, he in- 
forms me that he is convinced that by decomposition with 
acids blue chlorophyll yields phyllocyanin, whereas yellow 
chlorophyll gives phylloxanthin. It must be understood that 
the yellow chlorophyll of Sorby and the yellow chlorophyll, 
xanthophyll, &c., of other observers are quite distinct. 
The literature of chlorophyll contains descriptions of several 
substances, the properties of which closely resemble those of 
phylloxanthin. One of these is Pringsheim’s ‘ hypochlorin.* 
After immersing tissues containing chlorophyll in dilute 
hydrochloric acid, Pringsheim observed the formation, after 
some time, of peculiar brown, crystalloid, sometimes even 
crystallised, bodies, attached to, and proceeding from, the 
chlorophyll-corpuscles of the cells, and which he supposed to 
pre-exist in the latter, the acid merely serving to bring them 
