An Introduction to a Biology 



the suggestions of Interpretation, and always will be ; for 

 they are inseparable companions. The former is tedious 

 without the latter ; the latter is not countenanced without 

 the former. 



We have seen that description is influenced by interpre- 

 tation. We have seen that interpretation is not always 

 right. We therefore cannot escape the conclusion that 

 description is sometimes wrong. And even if this argument 

 did not prevent our escape from this conclusion, we could 

 not escape from it unless we shut our eyes to the hosts of 

 instances of it that are afforded by a study of the history 

 of the interpretation of nature. The pages of that history 

 are strewn with the carcasses of descriptions of things that 

 are not. Instances of such will crowd up into the mind of 

 the reader. For who is not familiar with numbers of cases 

 in which a man with a definite interpretation of a pheno- 

 menon in his mind has expected to find such and such a 

 thing, and has found it, in spite of the fact, incontrovertibly 

 established by general and impartial testimony afterwards, 

 that nothing of the kind existed all the time ? 



The upholders of the doctrine of evolution, as opposed to 

 that of epigenesis, asserted that a miniature edition of the 

 adult bird could be seen in the hen's egg. Hartsoeker 

 actually made a drawing of a spermatozoon in which a little 

 man is seen crouching with his knees tucked up to his body 

 and with his hands holding his knees in place. 1 



No sooner had the wonderful cytological phenomenon 

 which bears the name of the quadrille of centres been de- 

 scribed in the animal kingdom than it was promptly dis- 

 covered in the vegetable one. We know now that it exists 

 in neither. 



The leech Pontobdella is said to have a lateral blood-vessel 

 lying inside a lateral sinus, a part of the crelom. There is, 

 as a matter of fact, only one vessel, and this is homologous 



1 See Delage. " L'Heredite et les grandes problemes de la Biologie 

 generate," p. 380. 



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