HEART-BODY, ETC., OF CERTAIN POLYOHJITA. 277 



brown solution on boiling. Nitric acid completely dissolves the 

 granules after standing in the cold, and at once on boiling ; 

 the solution on evaporation leaves a yellow residue, which 

 gives the xantho-protein reaction, turning yellow on addition of 

 ammonium hydrate; but in many trials I never saw the purple 

 coloration of the murexide reaction. 



On standing in the cold in caustic soda the brown pigment 

 granules are dissolved, giving a fluid of a brownish-yellow 

 colour. On boiling a piece of fresh heart-body with caustic 

 potash, the pigment having been dissolved, some masses of 

 insoluble material remain floating about in the liquid. Con- 

 tinued boiling has no further eff^ect on them ; and on removing 

 them to a slide and examining them microscopically they are 

 shown to be composed of some irregular and granular debris, 

 but chiefly of clusters of bodies of an irregularly oval shape, 

 considerably creased and folded, translucent, in places colour- 

 less, but at some points brown, especially where they are 

 creased (fig. 13). Sometimes brown dots or circular markings 

 are scattered over their surface, whilst occasionally there is a 

 clear appearance of small tubular perforations of the walls 

 resembling the transverse striatious of some egg membranes. 

 These bodies are evidently the crumpled oval envelopes so 

 conspicuous in the spherical spaces of the heart-body ; but the 

 appearance of perforations is a new feature in them, revealed 

 by the action of the boiling alkali. It has already been sug- 

 gested that the openings thus shown may be the ways by which 

 the granular contents of the bodies are extruded. The re- 

 markable resistance of these bodies towards boiling alkalies 

 at once refers their material to a group of organic substances 

 of a chitinous nature. 



I asked Prof. Paul Mayer whether any further tests could 

 be applied to solve the nature of this substance, which he was 

 so good as to examine, and he pointed out that its effect on 

 polarised light corresponds with that of chitin. He referred 

 me to Ambronn^s paper on the cellulose reaction of chitin (2), 

 and was so good as to perform the test there recommended 

 himself. I collected the insoluble remnants of half a dozen 



