Page:Bird-lore Vol 08.djvu/127

 The Amount of Science in Oology 97 The color of egg-shells, as demonstrated many years ago by Carus and supported by later workers, is due to chemical decomposition of blood poured over the egg as it descends the oviduct; the color exhibits that the parturi- tion is accompanied by pain, but does it show much more ? White eggs are colored in the same way, but by white pigments. If any laws of this coloration are to be worked out, they must be on the basis of a chemical study of the blood of the living bird at the time of oviposition, with due consideration to the length of sojourn of the egg in the oviduct and the vascular supply of the latter. Nothing with respect to their origin is to be explained from the colors of the deposited eggs. The most that has been accomplished by the comparison of egg-shells is that certain patterns of coloration hold for particular groups of birds. At the same time, however, it is known that in other groups, and apparently quite as natural ones, there is no such uniformity. This should make us cautious in ascribing particular genetic value to color patterns of egg-shells. Indeed, it appears to me probable that such patterns frequently have neither teleological nor phylogenetic worth, may be without relation to the light or other conditions of the environment, are merely expressions of the chemical nature of the parent bird, and, therefore, doubtless readily influenced by food changes. If oologists were scientific they would commence with the study of the eggs of the ancestors of birds, the reptiles, and seek among extant birds for the ones with reptile-like eggs. In regard to abnormalities of form, size and color of egg-shells, — condi- tions so inexpressibly and yet so inexplicably dear to the heart of the egg collector, — these we shall not be able to understand until we can explain the normal conditions. Today examples of runt eggs and their like have no other value than that of curios. Their explanation is to be sought in abnormalities and malformations of the reproductive organs; they are to be associated with malnutrition or disease. These considerations might be carried out at much greater length, but they suffice to show, in the first place, that the great majority of oologists do not deserve the name of scientist, and, in the second place, that the subject of dead egg-shells admits of very limited scientific treatment. For scientific explanations are interpretations of genesis, and to understand we should study the parent in the first instance, and not the dead shell. The scientific study of eggs is that of the embryologist who considers the germ and its differentiation. But' how many oologists are familiar with the names and thoughts of Wolff, Pander, von Baer, W. K. Parker, His and Balfour ? These men have taught us more about the eggs of birds than all the thousands of oologists who have collected egg-shells. Oolo- gists can tell one the technical name of the species, perhaps quote the 'A. O. U. number,' and recall numbers and colors, and thereby think they hold the quintessence of knowledge, but this is no more than statist! -