64 THE EVOLUTION OF MAN. 



the same four layers which Baer had previously assumed. 

 The upper part of the middle layer after its cleavage 

 (Baer's "Flesh-stratum"), Remak calls the skin-lamella 

 (Hautplatte, or better, Hautfaserplatte); it forms the outer 

 wall of the body (the true skin, cutis vena, the muscles, 

 bones, and the like). The lower part (Baer's "Vascular 

 stratum"), he calls the intestinal-fibrous lamella (Darm- 

 faserplatte) ; it forms the outer covering of the intestinal- 

 canal, and of the heart, the blood-vessels, and so on. 



Based on the firm foundation which Remak thus supplied 

 to the History of the Evolution of the Tissues, or the science 

 called Histogen} 71 , numerous investigations of special points 

 which have considerably extended our information have 

 been made. Of course many attempts have been made 

 to give much narrower limitations to Remak's doctrines, or 

 to remodel them altogether. Reichert, of Berlin, and Wil- 

 helm His, of Leipsic, have specially busied themselves to 

 establish, in comprehensive works, an entirely new view of 

 the evolution of the body of Vertebrates, according to which 

 the rudiments of the body of the Vertebrate does not consist 

 solely of the two primary germ-layers. But these works, 

 owing to their total lack of the necessary knowledge of 

 Comparative Anatomy, and clear knowledge of Ontogeny, 

 and to the fact that they do not even glance at Phylogeny, 

 could exert but a very transient influence. Only the total 

 want of critical ability and comprehension of the real 

 problems of the History of Evolution can explain the fact 

 that many people for a time regarded the strange fancies of 

 Reichert and His as a great gain. 



His, in 1868, in a large book, on " The Early Evolution 

 of the Chick in the Egg," detailed his entirely erroneous 



