Constituents of Thames Mud. By Lionel S. Beale. 9 



has been exposed to the action of the digestive fluids poured into 

 different parts of the ahmentary canal, after it has passed through 

 the sewers, and after it has been carried backwards and forwards by 

 the tide, and exposed perhaps for months to various disintegrating 

 actions constantly taking place on the mud-banks of the 1 hames. 

 Spiral vessels, plate I. figs. 1 c*, 2 ; plate II. figs. 4 e, 8 ; plate III. 

 fig. 11 ; plate IV. figs. 13 c, 14. 



Starch-granules, 



In several specimens of mud I have found starch-grains, and 

 have been able to distinguish wheat starch, potato starch, and rice 

 starch by the shape and size of the grains and by the action of 

 iodine. Many specimens of wheat starch are much altered, and 

 look as if partly digested. These I think have probably been 

 derived from bread, and have passed through the alimentary canal. 

 Starch has also been found in many cells of vegetable tissue, the 

 exact nature of which I have not been able to determine. 



Muscular Fibres. 



In almost every specimen of Thames mud examined by me 

 muscular fibres or bodies which were recognized as the result of 

 changes in muscular fibres were found. The fragments varied much 

 in number as well as in size in different specimens of mud, but 

 were most numerous and the anatomical characters of the fibres 

 most distinct in the sewage taken direct from the mouth of the 

 sewer and in the muds near the outfall. Many of the fibres were 

 firm and hard, and had all the character of muscular fibres which 

 had escaped the action of the digestive fluids in their passage along 

 the alimentary canal, and which are very frequently, though not 

 constantly, found in faecal matter. The fibres in question are for 

 the most part derived from beef It is most interesting to study 

 the changes which may be observed in the character of the fibre as 

 it passes from the condition in which it is found in recent faeces, 

 with its well-known and remarkably well-marked anatomical cha- 

 racters, to its final disintegration in the river and on the mud- 

 banks of the Thames. Some of the most remarkable alterations in 

 the microscopical characters of the fibres are illustrated in my 

 preparations and represented in my drawings. In fresh faecal 

 matter some of the fibres exhibit the ordinary character of coagu- 

 lated and well-cooked muscle tissue which has escaped the action 

 of the gastric juice and intestinal fluids. The transverse markings 

 are very distinct and are sharply defined, the fibres are firm and 

 hard, and bear considerable pressure without being damaged. 



In other specimens the action of the digestive fluids upon the 

 fibres is very manifest, all appearance of transverse striae being lost 



