Reptiles

Animals with only 1 ventricle in the heart and still possessing a respiratory lung, but an incomplete one.

Their skin is smooth or furnished with scales.

In the third rank are placed, naturally and necessarily, the reptiles. They are going to provide us with new and greater proofs of the degradation in organic structure from one end to the other in the animal chain, starting at the most perfect animals.

In fact, we do not see again in their hearts, which have only one ventricle, the structure which really belongs to the animals of the first and second ranks. Their blood is cold, almost like that of the animals of the later ranks.

Another proof of the degradation in organic structure of reptiles is presented to us in their respiration. First of all, these are the last animals to breathe by means of a real lung. For, after them, we do not see again in any of the animals in the following classes a respiratory organ of this sort (something I will try to establish in discussing the mollusks).

Then, with the reptiles, the lung, in general, has very large chambers, proportionately fewer in number and already much simplified. In many species, this organ is missing in the early ages and finds itself then replaced by gills, a respiratory organ which we never find in the previous ranks. Sometimes here we find the two sorts of respiratory organs mentioned simultaneously in the same individual.

But the greatest proof of the degradation concerning the respiration of reptiles is that there is only one part of their blood which goes through the lung, while the rest reaches the parts of the body without having received the influence of respiration.

Finally, with the reptiles, the four limbs essential to the most perfect animals begin to be lost, and many of them (almost all the snakes) even completely lack them.

Apart from the degradation in the organic structure acknowledged in the form of the heart, the temperature of the blood, which is only just above that outside in the environmental surroundings, the incomplete respiration, the almost gradual simplification of the lung, we notice that the reptiles differ considerably among themselves.

The result is that the animals in each of orders of this class display greater differences in their organic structure and in their exterior form than those of the two preceding classes. Some live habitually in the open air, and among them, those which do not have legs can only crawl. Others live in water or at the water’s edge, moving back, sometimes into the water and sometimes into open places.

There are some which are covered in scales and others which have a bare skin. Finally, although they all have a heart with one ventricle, in some there are two auricles and in others only one.

All these differences are relevant to environmental circumstances, ways of life, and so on, circumstances which, undoubtedly, have a more powerful influence on an organic structure which is still some way from the goal to which nature tends. These circumstances were not able to exert such an influence on those animals more advanced in their improvement.

Thus, the reptiles are oviparous animals (even those whose eggs are enclosed in the womb of the mother), have a modified skeleton, very often very degraded, display a respiration and a circulation less perfected than those of mammalian animals and birds, and all manifest a small brain which does not completely fill the skull cavity. Thus, they are less perfect than the animals of the two preceding classes and confirm, on their part, the increasing degradation in organic structure, as we move closer to the most imperfect animals.

Among these animals, apart from the modifications to the shape of their parts resulting from the circumstances in which they live, we notice, in addition, traces of the general degradation in organic structure. For in the last of their orders (in the batrachians), individuals in the early stages breathe by gills.

If we consider the lack of legs (which we see in the snakes) a consequence of degradation, then the ophidians would make up the last order of reptiles.

But to accept this idea would be a mistake. In fact, the snakes are animals which, in order to conceal themselves, have acquired the habit of crawling right on the ground.

Their bodies have attained a considerable length disproportionate to their size. Now, the long legs would have hindered their need to crawl and hide, and very short limbs, which could only have been four in number (since these are vertebrate animals) would not have been capable of moving the body.

Thus, the habits of these animals made their limbs disappear. Nonetheless, the batrachians, which do have legs, display a more degraded organic structure and are closer to fish.

The proofs for the important idea I am setting down will be established with reliable facts. Consequently, they will always be beyond the challenges which people might like in vain to offer in opposition to them.