2 1 2 DAR WIN. 



The ExMbryologists. 



Let us first glance at the embryologlsts. Meckel 

 (i 781-1833) followed Wolff (i 735-1 794) in the series 

 of German founders of Embryology. Wolff had 

 emphasized the transmutations of structure, so that, 

 from seeds on the one side and eggs on the other, 

 came the many and diverse organisms. Meckel 

 more clearly anticipated Von Baer in 181 1, in the 

 passage: "There is no good physiologist who has 

 not been struck, incidentally, by the observation 

 that the original form of all organisms is one and 

 the same, and that out of this one form, all, the 

 lowest as well as the highest, are developed in such 

 a manner that the latter pass through the perma- 

 nent forms of the former as transitory stages." 



Von Baer, in 1834, in a lecture entitled "The 

 Most General Laws of Nature in all Development," 

 maintained that : " Only in a very childish view of 

 Nature could species be regarded as permanent and 

 unchangeable types, and that, in fact, they can be 

 only passing series of generations, which have de- 

 veloped by transmission from the common origi- 

 nal form." (See Haeckel, Vol. L, p. 112.) Serres, 

 in his Precis d' Anatontie Transce^idente (1842, 

 p. 135), enlarged the arguments of Meckel, and 

 showed that the missinsf links in the chain of Evo- 

 lution may all be discovered, if we seek them, in 

 the life of the embryo. When we compare animals 

 arrived at their complete development, we find many 



