NATURAL SCIENCE: 



A Monthly Review of Scientific Progress. 



No. 25. Vol. IV. MARCH, 1894. 



NOTES AND COMMENTS. 



Haeckel. 



" It gives furiously to think," as the Saturday Review dehghts to 



put it, that Ernst Haeckel was born only sixty years ago ; for those 



of us whose scientific education dates within the last two decades have 



been accustomed to regard him as a necessary pillar of the world of 



thought. Morphology, promorphology, the categories of individuality, 



the gastraea theory, the comparisons of vertebrate embryos, the 



natural history of creation, and the blundering incapacity of those 



who doubted it, were no small part of the intellectual pabulum of our 



scientific youth. We learned from him that the animal kingdom was 



a set of pieces to be arranged in orderly procession from Protista to 



Man ; that to study the embryology of an animal was to unwrap an 



Indian puzzle-box, piece within piece, and each piece suggesting the 



animal next behind in the procession of all the animals. We learned 



from him to invent logically hypothetical ancestors, and to find living 



animals to tally with them. It was all so cogent and so stimulating, 



and now, with fuller knowledge, so easy to jeer at and discredit. No 



one goes now to Naples to discover in the development of an animal 



exactly what he knows should be there : even a new discovery of the 



ancestor of all the vertebrates is somewhat blown upon. We 



elaborate methods, work out details, and mutter sadly : — 



" Embryologists we, 

 But we haven't got everything down in the sea." 



It is a history common to all great ideas. They explain so much 



at first, open so many new vistas, lead to advances so great that they 



seem master-keys to all the secrets of nature. And then a time 



comes when the potent explanation becomes impotent ; a time when 



one set of men seeing only how much it has explained, distort things 



it cannot explain into formal harmony, while another set, seeing only 



what it cannot explain, attempt to discredit it altogether. The cell 



theory and the recapitulation theory are now in this condition, and 



Haeckel, partly because of the intimate connection of so much of his 



u 



