OF SOUTH CAROLINA. 55 
Darwin mentions that on a certain occasion, during his researches in South America, his guides, 
who had long known of the existence of the skeletons of the mastodon, buried in a cliff, on the 
Pampas, puzzled to account for their position, at length came to the conclusion that the mas- 
todon was a burrowing animal! 
Modern researches have removed every doubt connected with the origin and history of intestinal 
worms. The Distoma hepatica, an animal confined to the livers of animals, particularly to those 
of the Ruminantia, has been supposed to offer peculiar difficulties. Sheep, when théy graze in 
low, wet pastures, are subject to diseases caused by attacks of these animals. 
A Swedish naturalist has the merit of being the first to point out the origin of these worms. 
He observed that at a certain season a species of fresh water mollusc was infested with small 
worms. He found them at first attached to the skin, at a time when they abounded in the water. 
They bury themselves in the animal, where they remain until one of those changes takes place, to 
which insects are subject. It is now provided with the means of penetrating the body, which it 
does till it reaches the cavity where the viscera are contained, to which it attaches itself, and where 
it continues to live and propagate. 
Prof. Eschrich has investigated with equal success the history of intestinal worms. He observed 
that periodically fishes were found with long worms in the alimentary canal, while at other times 
they disappeared altogether. Following up these investigations, he traced these worms through 
all their stages of growth, until they became long worms with articulated bodies and a small head. 
He observed that they shed the greater portion of the body at certain seasons; he found, moreover, 
that each joint of the portion thus cast contained hundreds of eggs, which, escaping into the water, 
would be swallowed by fishes along with their food, and would of course re-appear in the form of 
worms in the alimentary canal. 
One of the most curious facts observed during the investigation of the Natural History of Dis- 
toma, is that this animal is subject to several metamorphoses, and it requires several generations for 
the newly hatched animal to arrive at the state of the original parent. 
If, then, some of the most difficult cases connected with the origin of these obscure forms of 
being, have been thus successfully investigated, is it not reasonable to conclude that every case may 
admit of a like satisfactory explanation? Let us now take a brief glance at the transmutation 
theory. 
Life somehow commenced, Maillet and Lamark supposed the earlier organisms endowed with a 
power which they called appetency. This power, exerted for a long time in a particular direction, 
produced new organs or modified the old ones. For instance, one can suppose that a primeval 
oyster, tired of lying on its side, might entertain an intense desire to promenade the beautiful coral 
groves in its neighborhood. Such a desire, long continued, say these philosophers, would produce 
an extension of the abdominal muscles, which, after a while, would be protruded like a foot, by 
means of which the oyster could move about. The shell of the oyster would be inconvenient, 
on account of its unequal valves: some strong desires to remedy this, would no doubt occupy the 
mind of the oyster, and the result would be that, in a few generations, this shell would be altered 
to one of symmetrical form, such as that of the clam, which is far more convenient for locomotion. 
The desire to feel and to see would next be felt, and the tentacule and eyes of the gasteropod 
would appear. These causes continued, the oyster, in its upward progress, would arrive at the 
