Page:Popular Science Monthly Volume 86.djvu/311

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in science has always been controlled by circumstance. Had Harvey possessed the microscope that a few years after his demonstration of the circulation of the blood Malpighi was applying with distinguished success to the investigation of anatomical problems, he would not have failed to see the capillary network that escaped his unaided eye. And it is a question whether Darwin would have opened the famous notebooks that led after twenty years to the "Origin of Species" had he not been struck by the distribution of animals in South America and the Galapagos Archipelago. . The embryology of Amphioxus gives obvious support to theories of the formation of the germ layers and of the mesoderm by coelomic pouches that no student of earthworms alone, however diligent, could have constructed. And there is little doubt that Mendel's choice of the garden pea for his investigations on hybridization was a most potent factor in leading him so definitely and speedily to the annunciation of the well known propositions which have changed the entire course of researches in heredity during the last fifteen years. To the student of physics, the facts of nature assume a quantitative aspect that students of biology are only here and there beginning to recognize. Similarly, the sociologist and the psychologist are now dependent upon biological facts which have lost for the biologist much of their original interest through the development of problems that demand investigation of still more fundamental mechanisms. In the domain of a single science one finds the same connection between experience and ideas. To the investigator of the more generalized types of organisms that respond readily to a wide range of environmental conditions, the laws formulated by investigators of more complex and less plastic organisms seem strangely inadequate; while to the investigator who has discovered them they possess a clarity of outline that affords a welcome substitute for more vaguely expressed, even though more fundamental, conclusions. His eyes filled with the images of secondary adaptations in nature, a behaviorist may formulate his explanations in terms of selection and survival. Whereupon he meets with spirited opposition from the physiologist whose passion it is to reduce vital phenomena to the mechanical terms that have already succeeded in freeing physics and chemistry from the clutch of anthropomorphism.

To understand the Pacific states it is necessary to keep in mind this essential fact, that ideas are dominated by experience. Geologically, geographically, faunistically, socially, economically, the Pacific states form a natural empire distinctly set off from the rest of the country. Mountains and deserts have determined for them a certain isolation that has governed their settlement, the character of their population, whether plant or animal, the development of their institutions, their scientific progress. The region is not only new, but possesses many characteristics that do not ordinarily belong to the experience of citizens of other states.

Some of these recognition marks it is the purpose of this number to consider. The much-vaunted climate of California runs the gamut from typical desert conditions to Alpine, from regions of almost hopeless aridity to regions where humidity becomes an extreme in the other direction. Such diversity is strikingly correlated with floral peculiarities, as one of the papers in this number will show. Under the atmospheric conditions of central and southern California are found the two