192 Sir Everard Home’s observations 
In this section the septum is in part wanting, the muscular 
coat of the urethra is thinner, and there is no open space in 
the centre of the corpora cavernosa. 
Plate XIX. 
Consists of four figures, taken from a penis in which the 
corpora cavernosa and corpus spongiosum had been injected 
by the arteries with spirit, and then allowed to harden in 
spirit; the urethra had also been injected with spirit, and 
kept distended. 
Fig. 1. This section was taken near the root. The parts 
are nearly the same as in the last Plate ; they are only mag- 
nified two diameters. 
Fig. 2. A very small portion of the trellis work of one of 
the corpora cavernosa of the same section ; magnified fifteen 
times in diameter. 
Fig. 3. Another transverse section nearer the glans, mag- 
nified two diameters. In this the cavity in the corpora caver- 
nosa is seen, and the membrane of the urethra is thrown 
into folds. 
Fig. 4. A very small portion of the last section ; magnified 
fifteen times in diameter. 
Plate XX. 
Consists of three figures, taken from a penis, the corpora 
cavernosa of which were injected with mercury by the ar- 
teries, and the mercury was retained there by plugging up the 
trunks with common injection. The parts were then dried, and 
a longitudinal section made so as to let the mercury escape 
and leave the trellis work empty. In this state the preparation 
is kept in oil of turpentine. 
