The Sloth

When willpower determines that an animal carry out some action or other, the organs which must execute this action are immediately stimulated by the inflow of subtle fluids (the nervous fluids).

• These become the cause of the movements.

From this it follows that multiple repetitions of these actions of the organic structure strengthen, extend, develop, and even create organs essential for these actions.

It is only necessary to observe attentively what happens everywhere in this matter to become convinced of the basis for this cause of developments and organic alterations.

Every change acquired in an organ by a habitual use sufficient to have brought it about then preserves the change by reproduction, if it is common to individuals which, in the act of reproduction, come together for the propagation of their race.

Finally, this change passes itself on and thus is transmitted to all the individuals which come after and which are subject to the same circumstances, without being obliged to acquire the change in the same way it was actually created.

In the reproductive unions, the blending of individuals who have different qualities and forms is necessarily opposed to the constant propagation of these qualities and forms.

In man, who is subjected to so many diverse influential circumstances, that is what prevents the accidental qualities or defects which he happens to acquire from preserving and propagating themselves by reproduction.

If we have a case where two individuals with remarkable shapes or any defects always couple together, they will reproduce the same particular features, and if later generations limit themselves to similar unions, a particularly distinct race will then be formed from them.

Constant interbreeding among individuals who do not have the same distinctive features will erase all distinctive particularities acquired by distinctive circumstances.

Hence, if the distance between their dwelling places did not separate human beings, the reproductive mixing would do away with the general characteristics which distinguish the different nations.

The structure of individuals and their parts, their organs, their capacities, and so on are the result of the circumstances which each race finds itself subjected to by nature and of the habits which the individuals making up a race have been obliged to acquire.

These are not the result of a form existing in primitive times which has forced animals into those habits which we know about.

The animal called the ai, or the sloth (bradypus tridactylus) is constantly in a feeble state.

• It carries out only very slow and very limited movements
• It moves on the ground with difficulty.

Its structure is entirely linked to its feeble condition.

Hence, by assuming that this animal had received from nature the organic structure which we know about, people said that this organization forced upon it the habits and the sorry condition in which it finds itself.

I do not believe it.

I am convinced that the habits which individuals of the sloth family were forced to acquire originally must necessarily have led to its present condition.

If continual dangers had in earlier times brought it about that individuals of this species took refuge in the trees, habitually lived there, and derived nourishment from their leaves, then it is clear that they would have had to forgo a multitude of movements which animals living on the ground are in a position to carry out.

The needs of the ai would thus have been reduced to:

• hanging from branches
• crawling or dragging themselves to catch leaves
• remaining in the tree in an inactive state so as to avoid falling down

This style of inactivity would have been constantly fostered by the hot climate because heat encourages rest among warm-blooded animals rather than movement.

Over a long period of time, the individuals of the sloth family would have continued the habit of remaining in the trees and not moving much.

This will result in:

1. Their arms growing longer from constant efforts to hold onto the tree’s branches

2. Their nails being long and a hooked

3. Their long digits would never be exercised with remarkable movements and so they would lose their mobility, grown together, and preserved only the ability to clench or unclench together

4. Their thighs would continually wrap around the trunk or large tree branches, creating a space between them

This would help enlarge the pelvis and push the cotyloid cavities towards the back.

5. Their bones would have fused together

The fact is that the various animals all have, in accordance with their genus and their species, particular customs and always an organic structure which accords perfectly with these customs.

Thus, I can admit:

• either one or the other of the two following conclusions
• neither of them can be proven