DR. C. A. MAC MUNN ON ENTEROCHLOROPHYLL, AND ALLIED PIGMENTS. 257 
Absence of Starch and Cellulose, and Morphology of Enterochlorophyll. 
In none of the above cases was chlorofucin found; and I have shown in my paper 
“ On the Chromatology of Actiniae ” it ought to be present if symbiotic algae are 
present, and in animals living on marine algae it ought to be present if the “liver” 
chlorophyll be due to intracellular digestion of food chlorophyll. It was also 
necessary to see whether starch and cellulose were present, and to attempt to study 
the morphology of the pigment. The results strikingly confirm the spectroscopic 
evidence and support the idea that enterochlorophyll is built up by the animal. 
I found the best results were obtained by freezing the “ livers ” and examining the 
frozen sections. For this purpose the small ether-freezing microtome of Cathcart 
answers admirably. The freezing method has to be adopted since if the tissues are 
hardened in alcohol the chlorophyll is removed; and alcohol would be required 
because other hardening agents alter the pigment. The relationship of the entero¬ 
chlorophyll to the gland cells is, however, difficult to make out in frozen sections, but 
I think it is found in all cases within the epithelium cells lining the “ liver ” tubes. 
I made various sections of invertebrate “livers” obtained from animals feeding and 
fasting, but never obtained a trace of starch or cellulose with iodine in iodide of 
potassium, Schulze’s fluid, or with iodine and sulphuric acid. These experiments 
were made on the “ livers ” of Helix aspersa, Anodonta cygnea, Patella vulgata, Ostrcea 
edulis, Mytilus edulis, Astacus fuviatdis, the coeca of starfishes, &c. The precautions 
recommended by Geddes :* of previously digesting the tissues in alcohol, and in 
caustic potash, and neutralising with acetic acid, having been adopted in each case. 
Now, if food-products were present we ought to get starch or at least cellulose ; 
and if symbiotic algse were present the product of their activity, starch, and the 
cellulose wall of the alga itself, should be present; but they are not; hence these tests 
alone furnish a strong argument in favour of the purely animal origin of entero¬ 
chlorophyll. 
A section of the “liver” of Ostrcea edulis under a low power such as a 1-inch or 
2-inch shows tubes cut in different planes, oblique, transverse and longitudinal, and the 
pigment appears to be distributed mainly along the periphery! of the tubes, the centre 
of each tube in cross-section contrasting strongly with the periphery, the former 
being colourless, the latter deeply coloured. The pigment appeared in the form of fine 
granules, some yellow, some brown, and others of intermediate tints. The granules 
are not all round, some being angular. In teased-out specimens the pigment seemed 
disposed in bands along the long diameter of each tube, and in cross-sections of the 
tubes a section of four such bands forming a kind of cross can be seen. Besides 
* “Nature and Functions of the ‘Yellow Cells ’ of Radiolarians and Ccelenterates.” Proc. Roy. Soc., 
Edinburgh, vol. 11 (1882), p. 377. 
f Not the extreme periphery is meant, but that portion between the centre and the wall of the tube, 
i.e. the secreting part. This is only seen in cross-sections. In teased-oul specimens almost the whole 
tube appears coloured. 
2 L 
MDC'CCLXXXVI. 
