THE CELL THEORY. 6 1 



composed of cells? These were the important questions 

 which the Cell Theory at once raised in the study of Em- 

 bryology. 



Several naturalists attempted in different ways to 

 furnish the right answers, but the excellent " Investigations 

 into the Evolution of Vertebrates," by Robert Remak, of 

 Berlin (1851), became conclusive. By somewhat remoulding 

 the Cellular Theory of Schleiden and Schwann, this gifted 

 naturalist was able to overcome the great obstacles which 

 this theory, in its first form, had placed in the way of 

 Embryology. It is true that the anatomist, Karl Boguslaus 

 Reichert, of Berlin, had previously attempted to explain the 

 origin of the tissues. But this attempt was necessarily a 

 total failure, owing to the fact that the extraordinarily 

 confused mind of the author was equally destitute of every 

 correct idea of the History of Evolution, of the Cellular 

 Theory as a whole, and of a sound view of the structure 

 and development of tissues in particular. The inaccuracy 

 of Reichert's observations, and the falsity of the conclusions 

 drawn from them, is shown by every accurate test applied 

 to his so-called discoveries. By way of illustration, it may 

 be said that he declared the whole of the upper germ-layer, 

 from which the most important parts of the body — brain, 

 spinal cord, outer skin, and the like — proceed, to be merely 

 a transient " enveloping-skin " of the embryo, and that it 

 had nothing to do with the formation of the body ; that 

 many of the first formations of the separate organs did not 

 proceed from the primary germ-layers, but came one by 

 one from the yelk of the egg, and joined the layers after- 

 ward. Reichert's preposterous embryological labours suc- 

 ceeded in gaining a passing attention, only because they 



