It is very easy to go too far in drawing analogies between biology and sociology. Society--as yet, at least--is not an organism in the sense that a tree or a mammal is. It is quite true that with the perfect organization and solidarity to which Socialists look forward the analogy will be more complete than it is to-day, but for the present we must always remember that, as the lawyers would say, "the cases are not on all fours." If we bear these reservations in mind laws drawn from natural science are often of the greatest aid in enabling us to understand the phenomena of psychology and sociology. One of the most helpful of these laws of science is the biogenetic law which is always associated with the great name of Ernest Haeckel, its most distinguished exponent. Doctor William Boelsche, in his book[39] on Haeckel, uses, to illustrate this law, the familiar example of the frog. The mother frog lays her eggs in the water. In due course a new little frog develops from each of these eggs. But the object that develops from them is altogether different from the adult frog. This object is the familiar fish-like tadpole. It finally loses its tail, develops legs, and becomes a frog. Doctor Boelsche discusses the matter as follows:-- "There are reasons on every hand for believing that the frogs and salamanders, which now stand higher in classification than the fishes, were developed from the fishes in earlier ages in the course of progressive evolution. Once upon a time they were fishes. If that is so, the curious phenomenon we have been considering really means that each young frog resembles its fish ancestors. In each case to-day the frog's egg first produces the earlier or ancestral stage, the fish, it then develops rapidly into a frog. In other words, the individual development recapitulates an important chapter of the earlier history of the whole race of frogs. Putting this in the form of a law, it runs: each new individual must, in its development, pass rapidly through the form of its parents' ancestors before it assumes the parent form itself. If a new individual frog is to be developed and if the ancestors of the whole frog stem were fishes, the first thing to develop from the frog's egg will be a fish and it will only later assume the form of a frog. "That is a simple and pictorial outline of what we mean when we speak of the biogenetic law. We need, of course, much more than the one frog-fish before we can erect it into a law. But we have only to look around us and we find similar phenomena as common as pebbles. "Let us bear in mind that evolution proceeded from certain amphibia to the lizards and from these to the birds and mammals. That is a long journey, but we have no alternative. If the amphibia (such as the frog and the salamander) descend from the fishes, all the higher classes up to man himself must also have done so. Hence the law must have transmitted even to ourselves this ancestral form of the gill-breathing fish.