In both these instances the narrators are of that class who do know what to observe, and how to observe it; and the facts, whatever explanation they may admit, are not to be dismissed as the result of imagination or mistaken observation."[149] It is remarkable that all the serpents to which the phenomenon is attributed are ovo-viviparous. Our common lizard, to which the facts just narrated doubtless belong (_Zootoca vivipara_), has the same property, which, however, appears to be by no means common among the Saurian races. This coincidence, while it would afford a handle to the deniers of the stated facts, in the assumption that the emergence of the living young from the abdomen, or their presence within it, has given rise to the notion--may have an essential significance and connexion with the phenomenon itself, on the hypothesis of its truth. That endowment, whatever it be, which enables the young to live and breathe in the abdominal cavity of the mother before birth, may render it easier for them than for others not so endowed to survive a temporary incarceration within the stomach after birth. Mr Newman does not know how to believe that a young and tender animal can remain in the strongly digestive stomach of a viper and receive no injury; but he has forgotten to take into the account the well-ascertained power that living tissues have the power of resisting the action of chemical re-agents that would instantly take effect upon them when dead. The walls of the stomach itself are not corroded by the gastric-juice which is rapidly dissolving the piece of meat within it. If the young animals can do without air for a while in their snug retreat, I do not think they would need fear the digestive operation. Air, I should suppose, _must_ be excluded from the stomach, unless the parent have the power of swallowing air voluntarily, for the emergency; but perhaps a cold-blooded animal like a reptile, with a sluggish circulation and respiration, might do with very much less fresh air than a mammal under similar conditions.