chlorophyll and which is able on this account to absorb energy from the sun. You see green plants microscopic unicellular plants living in the ocean are both in a solution containing all of the mineral constituents which they need for their food and they also are exposed to sunlight whose energy they absorb by means of chlorophyll. It is, therefore, somewhat advantageous for them to remain small and unicellular and not to divide into cells and then keep those cells in groups because they cannot then do as well—be surrounded on all sides by their nutriment media and are exposed on all sides to its sources of energy the sunlight, but when terrestrial life began there were conditions of difficulty and in order to meet those conditions of difficulty it would be necessary in order to be successful to develop means adequate to meet those difficulties and the needs of such life have been the occasion—not the cause—have been the occasion for the development of the structures needed to meet conditions of existence there.
Q—Some animal life have gone from the earth to the sea, have they not?
A—Yes, some complex animals have gone back into the ocean, whales and the seal, and a great many of the water birds that spend a considerable portion of their life on the sea have gone back from the land. Of that we are entirely confident on abundant evidence.
Q—The whale (and I am diverting just a little because of some other matter that came up), the whale suckles its young, does it not?
A—Yes.
Q—And how is the whale classified?
A—The whale is a mammal.
Q—Will you give us the definition of mammal?
A—There again I hate to give definitions, but I can tell you some characteristics of mammals.
Q—All right.
Mammals Described
A—Mammals, all of them, have hair—either developed or rudimentary—on some part of their body. The possession of hair is a mammalian characteristic, hair not being known outside the group of mammals. The little hair-like feathers of birds are true feathers and not hair. They differ fundamentally in their structure from hair, and mammals also suckle their young. The mammals all have a vertebra column—a backbone; they all have two pairs of limbs unless they have secondarily lost those through adaptation to conditions of life. The fore limbs and hind limbs—those limbs always have a shoulder or hip girdle. The bone in the trunk attached to a linear series of bones, running out in the arm or leg, finally coming to a group of transversally arranged bones in the wrist or ankle, succeeded again by almost uniformly—I think—in the mammals except through degeneration—five digits and that this a rather—there are other series of characteristics, but the mammalian eyes have certain characteristics and different glands in connection with the body and I might, if I stopped to think up my lesson, tell you fifty points that are characteristic of the order of the mammals in distinction from other organisms.
Q—Now in the classification of the scientist-zoologist, where does man come?
A—He is classed among the primates. Man is not a very highly evolved animal in his body. He isn't as highly specialized as a great many organisms. His hand, for example, is a very generalized structure, nowhere near as much specialized as the hand of a bird, but he clearly belongs among the mammals. A group well up, I think, toward what we could call the well elaborated members of that group physically.
Q—You might tell us just what you mean by primate, for the benefit of us lawyers?
A—Well, I think because the group has been regarded as including man, the group has been given the primacy, I suppose that some of the insects, if they were sufficiently intelligent, might question that, but we do not question it.
