1885.] Connective Tissue of Molluscs, 443 



To observe most of the following results, however, the more 

 complicated processes alluded to above are not really essential. I 

 therefore give a simpler process, whose results are sufficiently 

 accurate. 



The mantles of twenty Anodons (previously preserved in strong 

 spirit) are treated, after removing the adherent spirit with blotting 

 paper, with 3 oz. of boiling distilled water. While in the water, the 

 mantles are disintegrated as far as possible with a glass rod. The 

 mixture is freely shaken, and in a few minutes filtered. The filtrate 

 is rapidly cooled, and then twice its bulk of absolute alcohol is added 

 to it, and allowed to stand. The precipitate so obtained is taken up, 

 after washing with 90 per cent, spirit, in distilled water, and again 

 precipitated by absolute alcohol as before. 



Upon dissolving this precipitate in distilled water a bluish opalescent 

 solution is obtained which — f 



1. Gives mahogany colour with iodine solution — the colour 

 disappearing upon warming, and reappearing upon cooling. 



2. Gives no reaction with Fehling's solution upon warming. 



3. After digestion with saliva at 30 — 35° for about 10 minutes, the 

 solution gives Fehling's reaction. 



4. Is precipitated by 60 per cent, alcohol. 



The above is briefly the evidence of the occurrence of glycogen in 

 the mantle of Anodon. 



3. The Localisation of the Glycogen in certain Cells. 



By a little care the mantle may be split in half (this is performed 

 more easily with a spirit specimen). Placing one of the halves so 

 obtained upon a glass slip, epidermis downwards, and treating the 

 preparation with solution of iodine, a remarkable appearance is 

 observed. 



The tissues generally are hardly stained at all, but with the naked 

 eye it is seen that the connective tissue is copiously sprinkled with 

 dark brown dots. By the microscope these dots are found to be very 

 large vesicular cells, some of whose contents have been deeply stained 

 by the iodine. 



4. Some Reactions and Particulars of these Glycogenous Vesicles. 



For the study of these cells, thick sections of the frozen mantle of 

 Anodon or preparations of the "mesentery " of Helix are best. 



The vesicles are then seen to be very large round or oval cells, with 

 very brilliant (though not doubly refracting) contents. 



By treatment with water, the cells are emptied of contents 

 except the nucleus and the cell protoplasm, which is very small in 

 amount. By crushing, it is seen that the metaplasm (" endoplastic 



