The proper place to read of it is, as I said, the second volume of the _Morphology_. This volume has to give an account of the evolution of organic forms. What is given rather casually, almost Socratically, in Darwin is now developed into a number of strict laws. This method of expounding more or less hypothetical, new, and insecure ideas in the form of laws has since been frequently attacked. Some have been led by it to take the ideas as so many dogmas, and even to learn the laws by heart as if they were texts in Scripture. Others have then laid the blame of this dogmatic interpretation on Haeckel himself. It is quite true that there was the possibility of a misunderstanding. People do not always think for themselves, and the statement of a proposition in the form of a law may prove a pitfall for them. The blind learning of them by heart is always mischievous. On the other hand, it might be urged that the statement of the ideas in this bald way affords the best opportunity for a thorough and rational criticism of them, precisely because they give such pregnant expression to the writer’s meaning. I do not find that order and strict logical definitions have ever done any harm of themselves, whatever it is that is put in order and defined. On the contrary. People must confuse order sometimes with real dogmatism. Of this there is not a word in the whole book, while at an important juncture the reader is actually warned to be on his guard against undue pressure. “In this,” we read in the twentieth chapter, “we do not wish to draw up a body of laws of organic morphology, but to give hints and suggestions for drawing them up. A science that is yet only in its cradle, like the morphology of organisms, will have many important changes to undergo before it can venture to claim for its general propositions the rank of absolute and unexceptionable natural laws.” However that may be, it was in this provisional definition of laws that the famous biogenetic law first took shape, and with it a spirit entered into Darwinism in the narrower sense that was never again detached from its master, Haeckel. Let us once more take a simple illustration from facts. Take a green aquatic frog and a fish, say a pike.