284 Ingvar Jorgensen and Walter Stiles. 
from an ether solution by an equal volume of 25% hydrochloric acid, 
while with 32% it is almost entirely extracted: again only traces of 
phytochlorin e are extracted by 0-5% acid, but it is almost entirely 
extracted with 4 to 5% acid. The “ hydrochloric acid number ” is 
the percentage content of that acid which by shaking removes 
approximately two-thirds of the dissolved substance from an equal 
volume of an ethereal solution. 
It was thus possible to separate the decomposition products of 
phaeophytin by fractionating the mixture of them in ether with 
hydrochloric acid of different concentration. 
The formation of the large number of decomposition products 
of phaeophytin is due to the instability of chlorophyll in alcoholic 
solution. By uniform treatment of material, however, Willstatter 
has been able to ensure obtaining only two, but never fewer, 
decomposition products from phaeophytin: phytochlorin e, 
C 3a H a2 ON 4 (COOH) 2 , and phytorhodin g, C 32 H 30 O 2 N 4 (COOH) 2 . 
As the molecular weight of phaeophytin is of the same order 
of magnitude as that of phytochlorin e and phytorhodin g, and as 
these cannot be converted into one another, and as moreover they 
are formed in definite proportions by weight, it follows that they 
are formed from two different phaeophytins and ultimately from 
two different chlorophylls. 1 
The summary opposite may serve to make clear the action of 
different reagents on the chlorophyll molecule. In each case we 
have represented the actions with chlorophyll a. Similar reactions 
take place with chlorophyll b. 
Description of Chlorophyll. Chlorophylls a and b as precipitated 
out by petrol ether are microcrystalline. Chlorophyll a forms a 
blue black powder which makes a green mark. Chlorophyll b 
forms a green to green black powder. 
Chlorophyll a is easily soluble in ethyl alcohol, acetone, chloro¬ 
form, ether and carbon-disulphide, pyridin and benzene, moderately 
soluble in methyl alcohol and soluble with difficulty in 80% ethyl 
alcohol, 90% methyl alcohol (even warm) and petrol ether (even 
warm). It is practically insoluble in 80% methyl alcohol. 
Chlorophyll b has much the same solubility properties as 
chlorophyll a, except that the solubility is generally slightly less. 
It is completely insoluble in petrol ether and practically insoluble 
in 90% methyl alcohol. 
1 For further information on the chemistry of chlorophyll see Willstatter 
and Stoll (1913). A short account of the chemistry of chlorophyll has also 
recently been published by Willstatter in English ; see Willstatter (1915). 
