480 The University Science Bulletin. 



these general assumptions formulated by the earlier authors, but 

 quite the reverse, it has spoken against them. As Bayliss states, 

 there is not evidence that cells are necessarily dynamic. The best 

 morphological studies of protoplasm have again failed to show struc- 

 ture in many cells other than nucleus and centrosome. As Wilson 

 clearly states, cellular growth, division and differentiation are not 

 primary factors in development, but secondary to more formative 

 forces or stimuli. In the simple formulation which I have given above 

 it is possible to understand how the organism not only reproduces 

 itself, but it expresses definite need for the differential changes as 

 they come into existence. The energy for the primary building is 

 acquired from the old. The old is a machine not different in prin- 

 ciple from other machines of nature. 



As I shall show in the following pages, the main criticism of 

 Child's theory is that he utilizes theories to build theories. He ac- 

 cepts the idea of the cell as the unit of manifested life of the organ- 

 ism without question. Before any theory of life and death is justi- 

 fiable of acceptance it is necessary that the true nature of the struc- 

 ture and the metabolism of the cell be ascertained. This is not go- 

 ing to be accomplished by morphological and chemical methods 

 alone, nor by a study of the metabolism of the whole, but by 

 methods which allow us to study directly each of the fundamental 

 manifestations of life, such as growth, division, differentiation, 

 migratory movement, etc. The tissue culture has given us this 

 opportunity. In support of the above contentions it is of interest to 

 report here some general analyses so far carried out by this method. 



THE CONNECTIVE-TISSUE CELLS. 



As is well known, practically all previous work on the cell in re- 

 gard to the nature of its energy-producing reactions and the man- 

 ner of the transformation of this energy has been based upon the 

 idea that the cell is a highly organized body. While for years it has 

 been assumed that amoeboid movements are comparable to surface 

 tension changes in liquids, all theories have been based upon the 

 idea that these amcsboid movements are the result of localized 

 changes in surface tension resulting from some unknown organiza- 

 tion residing within the cell. All modern physiochemical methods 

 have failed, however, to reveal any such organization. This has led 

 one and then another to assume that the organization is either the 

 result of a slow diffusion of substance in the colloids of the cell 

 (Wells) ^, a peculiarity of colloids not yet organized, or to invisil'le 

 membranes traversing the protoplasm. 



