internal structure of the human brainy &c. 7 
The clear and distinct representations which Mr. Bauer 
has given of these very minute objects, has made it unneces- 
sary for me to take up the time of the Society in giving de- 
tailed descriptions of the different parts ; indeed any thing 
that is to be said, had better be stated in the explanation of 
the drawings, than connected With the general remarks 
which form the Lecture itself. 
The Snail having a brain of the same kind as the Bee, and 
the medulla spinalis having a similar structure, while the 
series of ganglions is wholly wanting, forms one of the most 
curious parts of this investigation. Having ascertained that, 
in all the animals, the structure of whose nervous system has 
been explained in the present Lecture, the brain is a distinct 
organ, varying in size it is true, till at last it is scarcely dis- 
tinctly visible to the naked eye, but when examined in the 
microscope, found to consist of globules and elastic trans- 
parent matter, and more or less of a fluid, similar to the brain 
of animals of the higher orders ; that there is also at some 
distance from the brain, a second substance of similar struc- 
ture, connected with the brain by two lateral chords ; and that 
this second part gives off the nerves that go to the different 
muscular structures of the body ; I consider myself borne 
out in the opinion that this part answers the same purpose 
as the medulla spinalis. 
The ganglions which form a chain connected so beautifully 
together by a double nerve, must be considered to have the 
same uses, whatever they are, as the ganglions in the human 
body, being equally composed of a congeries of nerves. 
These are facts, which if they are allowed to be clearly made 
out, form an addition to our knowledge, and give confirma- 
tion to opinions not before satisfactorily established. 
