394 PHILOSOPHY OF ZOOLOGY. 
The Seminal Fluid has never been examined with care 
in its pure state, or unmixed with the contents of the ve- 
sicles and prostate gland. In its compound state, Vau- 
QUELIN found that of man to be heavier than water, to 
be alkaline, and to consist, in the hundred parts, of 90 of 
water, 6 of mucus, 3 of phosphate of lime, and 1 of soda. 
The most remarkable character, however, of the seminal 
fluid, consists in the number of animalcula which are con- 
tained in it. These were first observed by one LEwts 
Hamme, and afterwards examined with care by LrEUwEN- 
HOEK and SpaLttanzant. They are exceedingly minute, 
and require, for their examination, a practised eye, aided by 
powerful magnifiers. The want of these qualifications led 
Bomare to deny their existence, and Linnaus to regard 
them as inert particles, set in motion by heat. They dif- 
fer in size and form in different species, and are found in 
the semen of oviparous, as well as viviparous animals. 
They move about in the fluid with a progressive motion, 
in various directions, and are easily killed by cold, or 
mixing the sperm with other liquors. 
These animalcules are not peculiar to the semen. Spat- 
LANZANI found them in the mesenteric blood of frogs, and 
newts, even females; in the blood of a sucking calf, and of 
a ram. 
It was the opinion of LrruwEnnoex, that these ani- 
mated beings were destined to expand into maturity, and 
ultimately to exhibit the forms of the animal in the semen of 
which they resided ; or that they were the germs of the ani- 
mal. Burron regarded them as organic particles, no 
longer required by the body for its support, but treasured 
up in the genital organs, and ready to unite with the or- 
ganic particles of the female, to give rise to a new indi- 
vidual. They are now generally regarded as excercising 
