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 LEWIS 

 HAMME, and afterwards examined with care by LEEUWEN- 

 HOEK and SPALLANZANI. They are exceedingly minute, 

 and require, for their examination, a practised eye, aided by 

 powerful magnifiers. The want of these qualifications led 

 BOM ARE to deny their existence, and LINN/EUS 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. SPAL- 

 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 LEEUWENHOEK, 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. BUFFON 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 exercising 



