39 
structure of the brain and nerves, &c. 
appearance vanishes when the parts are more minutely ex- 
amined. Its structure was made out in the following manner. 
Wednesday, August 23, 1820, at 12 o’clock, a healthy large 
spleen, taken from a man twenty-eight years of age, was cut 
into eight transverse slices, nearly of the same thickness ; four 
of these were put into one flat dish, and four into another; both 
of these were filled with distilled water ; no colouring mat- 
ter was given out, although the surfaces had all a red colour; 
the cells were unusually distinct, and had a degree of unifor- 
mity in their appearance. On examining the cells under 
water with a common lens, they appeared full ; on turning 
them over in the water, something colourless fell out, carry- 
ing no colouring matter along with it. The same thing hap- 
pened on turning up the opposite side. This appearance is 
represented in PI. VI. fig. 1. and 2. 
Aug. 24th, 12 o’clock. Some colouring matter was dis- 
charged round each slice, forming a circle round it, but not in 
contact with the edge. It had the appearance of red serum, 
but not that of the globules parting with their colour ; the sur- 
face lost its red colour, becoming darker. The cells were ex- 
amined by a lens, when those on the upper surface appeared 
hollow and empty, but those on the under surface appeared 
full of a mucus soaked in water, and a film was spread over 
the surface of several of them. The water was changed every 
day. 
25th, at 12 o’clock, both the upper and under surfaces 
were obscured by flocculent mucus over the cells, which were 
equally distinct ; the red colour was discharged in greater 
quantity. 
26th. Both surfaces had the mucus filling the cells, of a 
