n8 SCIENCE PROGRESS. 



derived from pre-existing germs, the latter must have 

 contained within themselves the principles of the former ; 

 hence the theory of " emboitement," or the inclusion of 

 germ within germ, which necessarily underwent considerable 

 modification as o-erms were regarded as organised bodies in 

 miniature, or as original preformations, immediate principles 

 from which the whole could be developed. The views of 

 Cuvier, adopted from Bonnet, as they are expressed in 

 Laurillard's " Eloge," are very similar to those of to-day, 

 and the reasoning which led to those views is parallel with 

 the reasoning which has led to the modern theories. Cuvier 

 believed in the pre-existence of a radical de Petre, a 

 radical which existed before the series of evolutions com- 

 menced, and certainly could be traced back for several 



generations. 



Has it occurred to those who assert that the fixed archi- 

 tecture of the germ determines the species, and that the 

 species has given its impress to the fixed architecture of the 

 germ (for this is what is meant by saying that the fixed 

 architecture is inherited), has it occurred to them that this 

 is only a restatement in another form of the old problem 

 "whether the chick gives rise to the egg or the egg to the 

 chick"? Trace back the successive production of germ from 

 organism, organism from germ ; try to form a mental picture 

 of the successive grades of complexity acquired by both and 

 transmitted from one to the other, and one is soon landed 

 in insuperable difficulties in spite of the formal solution 

 of Weismann. Whoever has faced this question and tried 

 to trace back the complex transmissions of characters has 

 arrived at the same conclusion, first expressed in a manner 

 acceptable to biologists by Weismann, but present to the 

 mind of Harvey, and before him to Aristotle, namely, the 

 continuity of the germ plasm. 1 



The " circuitus gallinaceus," as Harvey calls it, is 



1 " Facit namque hie circuitum gallinaceum genus sempiternum ; dum 

 modo pullus, modo ovum, continuata perpetuo serie, ex individuis caducis 

 et pereuntibus immortalem speciem producunt " {Exercit. de ge?ieratiotie, 

 Ex. xxviii.). 



