280 LIONEL JAMES PTOTON. 



at 60° C. for ten hours. It was then found to be coloured green^ 

 and numerous black dots were scattered about it.^ On exa- 

 mination with a J2-ii^ch objective these dots were seen to be 

 intensely stained granules, a crescent-shaped portion round 

 the edge of each of which was of a deeper colour than the rest. 

 Besides these, numbers of clearly defined and minute granules 

 were stained, especially in the outer cells of a strand of the 

 tissue. After 3 per cent, nitric-acid-alcohol acting for some 

 hours at 35° C. the results were the same, except that the 

 crescentic marking of the larger granules was not shown. In 

 tissue subjected to the action of Bunge's fluid for thirty hours 

 no trace of the reaction takes place. On the criteria laid 

 dow^n by MacAUum, the facts that iron is not, or only slightly, 

 revealed by the ferrocyanide reaction, but yet that it is shown 

 by the ammonium-sulphide method, whilst it is easily removed 

 by Bunge's fluid, go to indicate that it is in organic ('^mas- 

 kirt'^), but not in very elaborate combination. The presence 

 of iron-containing bodies and also of fat globules in especial 

 numbers in the peripheral cells is noticeable. It has been 

 mentioned that the fat dissolved from the heart-body by ether 

 was pigmented, and it may be here suggested that possibly this 

 pigment contains the iron. It is likely that the iron-holding 

 bodies are connected with the formation of the blood-pigment. 

 Barfuth's method of demonstrating glycogen microchemi- 

 cally (3) was applied to the heart-body, his mixture of glycerine 

 and iodine dissolved in potassium iodide solution being used. 

 Material fresh from the sea was chosen, and also worms placed 

 in an aerated mixture of starch and sea water. The worms 

 took up the starch, but neither in this nor in any case was a 

 clear red-brown colour obtained with the reagent, sufficient to 

 prove the presence of glycogen. 



The indications of all these reactions point to the following 

 conclusions as to the nature of the contents of the heart-body : 

 that the brown granules, being soluble in caustic alkali solu- 



* The nuclei did not markedly show the iron reaction. No doubt iron is 

 present in them, but for its demonstration, according to MacAUum's recipe, 

 the cells would have to be completely isolated from one another. 



