28 
INTRODUCTION. 
general ideas which we form respecting this process are tolerably clear, although we 
have no distinct or detailed notion of what passes at each point ; and for want of 
knowing the chemical composition of each part with sufficient precision, we cannot 
render an exact account of the transformations necessary to produce it. 
Besides the glands w'hich separate from the blood those fluids which perform some 
office in the internal economy, there are some which detach others from it that are to 
be totally rejected, either simply as superfluities, such as the urine, which is produced 
by the kidneys, or for some use to the animal, as the ink of the cuttle, and the purple 
matter of various other mollusks, &c. 
With respect to generation, there is one process or phenomenon infinitely more 
difficult to conceive than that of the secretions ; it is the production of the germ. We 
have seen even that it may be regarded as little less than incomprehensible ; but, the 
existence of the germ once admitted, generation presents no particular difficulty : so 
long as it adheres to the parent, it is nourished as if it were one of its organs* ; and 
when it detaches itself, it has its own proper life, which is essentially similar to that 
of the adult. 
The germ, the embryo, the foetus, and the new-born animal, have in no instance, 
however, precisely the same form as the adult, and the difference is sometimes so great, 
that their assimilation merits the name of metamorphosis. Thus, no one not previously 
aware of the fact, would suppose that the caterpillar is to become a butterfly. 
All living beings are more or less metamorphosed in the course of their growth, 
that is to say, they lose certain parts, and develope others. The antennae, wings, and 
all the parts of the butterfly were inclosed within the skin of the caterpillar ; this 
skin disappears along with the jaws, feet, and other organs that do not remain in the 
butterfly. The feet of the frog are inclosed by the skin of the tadpole : and the tad- 
pole, to become a frog, loses its tail, mouth, and gills. The infant likewise, at birth, 
loses its placenta and envelope ; at a certain age its thymous gland almost disappears ; 
and it acquires by degrees its hair, teeth, and beard. The relative size of its organs 
alters, and its body increases proportionally more than its head, its head more than its 
internal ear, &c. 
The place where these germs are found, the assemblage of them, is named the ovary ; 
the canal through which, when detached, they are carried forward, the oviduct ; the 
cavity in which, in many species, they are obliged to remain for a longer or shorter 
period before birth, the matrix or uterus ; the exterior orifice through which they pass 
into the world, the vulva. When there are sexes, the male sex fecundates ; the germs 
appearing in the female. The fecundating liquor is named semen ; the glands which 
separate it from the blood, testicles ; and, when it is necessary that it should be intro- 
duced into the body of the female, the intromittent organ is called penis. 
li 
•V ^ 
;ii 
till 
RAPID EXPOSITION OF THE INTELLECTUAL FUNCTIONS OF ANIMALS. 
The impression of external objects on the me, the production of a sensation, of an 
image, is a mystery impenetrable to our intellect ; and materialism an hypothesis, so 
much the more conjectural, as philosophy can furnish no direct proof of the actual 
Germs have been detected in the ovaria of a human foetus. — E d. 
