( H°5 > 
Fig. II. 
T*be inferior Surface of the fame Petrifyed Body, after 
the Membrane that inclofed it was taken off 
a The Hole by which it was difcoter’d to be hollow- 
B. The Fijfure by which it was divided, to fhew its 
infide expreft, 
Fig. III. 
C. Its Petrified Cells that contained the Hydatides of 
various Sizes and Figures, expreft at D when taken out. 
V. MicroJ copied ObferVations on the Structure of the 
Spleen , and the Probofcis of Fleas. ' !By Mr 
Anthony Van Leeuwenhoek, F. <1$. S. 
Delft , June i. ijc-6. 
A Mongft other things it has been obferved, that the 
Spleen is compos’d of a fpungy fort of Flefh : 
And having examined the Spleens of feveral Sheep, 
I found that the many Fibrous parts, of which it general- 
ly cutiiifts, and which many fuppofe to be Arteries and 
Veins, are in reality no Veins, but are united to, and 
dtew their 'Nourifnme'nt from the Membranes in which 
they are radicated, and fpread themfelves into many 
Branches, and join , with the Fibrous parts, which like- 
wife appear with Roots and Branches growing out of 
the bp polite Membrane, that I 'could not forbear viewing 
them with aftomfamentj 'imagining that all the innu- 
merable Fibrous parts -were conftituted to no other end, 
than to protrude the Blood which is conveyed into them 
by the Arteries j which Blood iji great quaud ies is con- 
tain’d in the Veins, as may appear in great meafint in thole 
Veins 
