FERMENTS AND MISCELLANEOUS PRODUCTS 93 



allied to haematin, the red colouring matter of blood. The 

 formula C34H 34 N 4 ClFeO5 has been ascribed to the latter. 

 Probably both substances are derivatives of pyrrol. 



CH=rCH x 



I >NH 



CH CH/ 



Chlorophyll is always associated with a certain amount of 

 ash constituents from which it cannot be entirely separated, or 

 only with great difficulty. The oxides of calcium, magnesium, 

 iron, and phosphorus predominate. It is uncertain which, if 

 any, of these are essential constituents of the molecule. The 

 presence of iron is at least indispensable to the formation of 

 chlorophyll whether it enters in the composition of the sub- 

 stance or not. 



Chlorophyll is an amorphous, neutral body, insoluble 

 in water, but readily soluble in alcohol and other organic 

 solvents. The ethereal solution is strongly fluorescent, i.e. it 

 exhibits a vivid green colour by reflected light, and a Ted 

 colour by transmitted light. The solution may be kept 

 indefinitely in the dkrk, but rapidly undergoes change on 

 exposure to light. The colour fades, and the substance is 

 broken up into a number of complex products of an acid 

 character. 



When ethereal solutions of chlorophyll are shaken up with 

 fuming hydrochloric acid and allowed to settle, the mixture 

 separates into two layers. The upper (ethereal) portion 

 exhibits a yellow colour, and has, in consequence, been called 

 phylloxan-thine or xanthophyll ; the lower (aqueous) portion 

 is blue, and has, therefore, been called phyllocyanine or cyano- 

 phyll. The latter reacts with certain salts chiefly compounds 

 of iron with organic acids, forming green solutions which 

 closely resemble the colour of the original chlorophyll. A 

 crystalline body called phyllotaonin, C4 H 38 O 5 N 6 , has been 

 obtained from cyanophyll by further treatment with hydro- 

 chloric acid and also by the action of alkalis. 



The composition and properties of lactochrome, the colour- 

 ing matter of milk fat, are quite unknown. 



Many other colouring matters, both of animal and vegetable 



