ON THE FILLING UP OF RIVER-BEDS AND HARBOURS. 131 



a manner, as to exert no injurious pressure on the vessels, while their 

 new contents impart that peculiar hue which characterizes the disease. 



It also throws no little light on the nature and source of the disease. 

 It seems to show that the fat is an increase of a normal constituent, and 

 not a formation altogether unnatural in kind ; thus distinguishing it 

 from the fatty degenerations of other tissues, where fat is deposited in 

 situations from which it is naturally absent. It likewise indicates an 

 increased activity in the secreting action of the liver, for a considerable 

 period before death, though why the accumulation of fat should occur 

 within nucleated particles does not so clearly appear. To explain that 

 fully, will require a more complete knowledge than we yet possess of 

 the chemical affinities at play within these small laboratories of nature. 



I cannot conclude without remarking, that the fact which has been 

 detailed, is an admirable example of the kind and degree of insight into 

 pathological changes, which the microscope is caleulated to afford. It 

 is happily unnecessary, in the present day, to come forward as the ad- 

 vocate of this invaluable instrument as an aid to the study of disease. 

 The fact is also of uncommon interest, as an illustration of the strict 

 subordination of the study of pathology, as well as that of minute anat- 

 omy and minute chemistry, as to semeiology and that coarse inspection 

 of morbid changes, which has too long usurped the name of morbid 

 anatomy. 



Explanation of the Figures, Plate III, Div. 6. 



A. Nucleated particles from the healthy human liver. 



B. The same, from the liver affected with fatty degeneration. 



a, a. Nuclei. b, b. Nucleoli. c, c, c. Fatty globules. 



XXIII. FARTHER OBSERVATIONS ON THE FILLING UP OF RIVER-BEDS 



AND HARBOURS, BY MICROSCOPIC ORGANISMS.* 



By M. Ehrenberg. 



SPECIMENS had been received from M. Hagen of the masses which had 

 been removed from the harbour of the Oder at Swinemiinde, and from 

 that of the Vistula at Dantzic. The masses which had been removed 

 at Swinemunde, amounted in 1839, to 2,592,000; and in 1840, to 

 1,728,000 cubic feet (German). 



Abstract of the Paper read before the Berlin Academy, 10th June, 1841. 



