8 Transactions of the Society. 



fatty acids. Even blood-corpuscles of man or of one of the higher 

 animals have been detected in the mud, having withstood all the 

 destructive agencies to which they have been exposed during 

 probably many months. Fragments of paper and rags and many 

 other things are also present, but it is to those substances which 

 are found in the excrements that my attention has mainly been 

 directed. 



Fragments of Vegetable Tissue in Thames Mud. 



In every specimen of mud examined many fragments of vege- 

 table tissue have been found, but considerable variation exists in 

 different banks, both as regards the character as well as the 

 quantity of vegetable tissue present. Some of the fragments of 

 vegetable tissue found in the mud of the Thames are doubtless 

 derived from plants which grow on the banks, and which in various 

 ways and from many sources find their way into the river; but 

 that the great majority of such fragments are derived from the 

 sewage and have already passed through the alimentary canal is 

 proved by the yellow colour they have taken from the faecal matter. 

 If healthy fseces be examined after a person has eaten a quantity 

 of cabbage or other vegetable, many fragments of vegetable tissue 

 stained of a deep yellow colour will be found, and the appearance 

 of these is very similar to that of many of the fragments seen in 

 my specimens of mud taken from the mud-banks. It is remarkable 

 that, in its passage through the intestines, colourless greenish or 

 pale-brown vegetable tissue becomes infiltrated with yellow colouring 

 matter, and is thus sometimes deeply stained of a bright yellow, 

 and this stain is very persistent. 



Spiral Vessels. 



In nearly all the specimens of mud I have examined I have 

 found fragments of spiral vessels, many of which are very large and 

 of great length. The majority are undoubtedly derived from the 

 common cabbage, while some are clearly connected with portions of 

 tea-leaves, of which numerous fragments have been discovered in 

 most of the specimens submitted to examination. 



If a portion of the stem of a well-boiled cabbage-leaf be ex- 

 amined numerous large spiral vessels exactly like those I have 

 found in the mud will be discovered. In most of them the mem- 

 brane of the vessel is destroyed or so softened by boiling that the 

 spiral fibre protrudes, and in many cases is almost entirely un- 

 coiled. On comparing these spiral fibres with many of those in 

 the mud the similarity will be at once recognized. The resisting 

 power of the spiral fibre is shown by the fact of its retaining its 

 remarkable characters not only after prolonged boiling, but after it 



