354 COMPARATIVE ANATOMY 



respects, relatively to certain categories of characters, and never 

 wholly. 



To homologize is to compare. Now, things are never so different 

 that we cannot compare them, nor so similar that the comparison will 

 not be false in some points. The tail of the dog represents almost 

 identically that of the jackal, a little less so that of the ox, a little less 

 that of the bird, a little less that of the serpent or of the fish; it does 

 not represent that of the scorpion or the crayfish, but it would be an 

 exaggeration to say that it has nothing in common with the last two. 

 One comparison is always permissible. When Oken compares the 

 vault of the skull to that of the heavens, there is this in his favor, that 

 one, like the other, is a hollow hemisphere having inside it something 

 which thinks. The mistake is made when we attempt to draw from 

 such distant resemblances consequences more exact or more ex- 

 tended. The mistake is the same, in a lesser degree, when, after 

 having homologized, for example, the radius with the tibia, we 

 imagine, as some of us have a tendency to do, that there is not in 

 one of these bones a single tuberosity or furrow which has not in 

 some more or less hidden form its representative in the other. 



What must we conclude from this study? 



Comparative anatomy is a science which arranges, classifies, sep- 

 arates, brings together, groups, and labels information, reunites 

 scattered facts under general formulas, compares, finds likenesses, 

 differentiates, subordinates, makes a hierarchy of characters. It is 

 the science of the study, the library, the museum. It borrows much 

 from nature through zootomy, paleontology, embryology, but it is 

 through meditation that it puts its materials to work. It attempts 

 at times to rise even to the explanation of phenomena, but always 

 in an indirect way and without hope of verification a posteriori, in 

 the way in which history explains politics. 



It is not a laboratory science. 



In that respect it is and it remains a science of the past. 



The future, in biology, is for experimental researches, those where 

 one puts on an apron, where one weighs, dissolves, corks up, heats, 

 filters, distends, compresses, shakes, sections, cuts, electrolizes, etc., 

 where one works with substances or with living beings which one sub- 

 mits to physical and chemical agencies or to conditions of life which 

 cause them to vary in a methodical manner in order to produce modi- 

 fications and thereby to discover, if possible, the causes of forms, 

 of structures, and of their variations. 



Does this mean that we must renounce comparative anatomy, 

 and that this science, in which the Saint-Hilaires, Cuvier, J. Miiller, 

 Owen, Gegenbaur, and many others have become famous, has no 

 further service to render? Certainly not. It continues to be in- 

 dispensable to all of those who are engaged in biology in order to 



