Cell-Theory not Sufficient for Explaining Organism 189 



tin- same tinu- host authenticated instances of transformation 

 of tissues accompanying the replacement of lost parts has 

 been described by Nusbaimi and Oxner. The results of their 

 researches significant for our present needs arc summarily 

 stated in the translation which follows: "From what has 

 been said above, we see that in the regeneration of the an- 

 terior part of Linen n loctctix, which has been robbed of the 

 entire old alimentary canal, the formation of new tissues 

 takes place heterogenetically in the highest measure; that 

 is, it proceeds in such a way that the new tissues arise from 

 an entirely strange old tissue from which they are never 

 produced under normal conditions. We saw, that is to say, 

 that the epithelium of the entire new alimentary tract, a 

 tissue endodermal par excellence, is formed in regeneration 

 by wander-cells which arise from the parenchyma and con- 

 nective tissue, therefore from a material originally wholly 

 mesodermal." s The elaborate description and illustration 

 with which they present their observations leaves little to be 

 desired for making the case trustworthy, even had it not 

 been confirmed by other workers. Fortunately, however, C. 

 Dawydoff, a Russian xoologist, working on the same species 

 at the same time but wholly independently, reached results 

 identical in every essential particular. 



DawydofPs categorical statement touching the main point 

 is as follows: "The newlv-arisen alimentary canal of Linens 

 lac ten* is formed from mesoderm. It is differentiated from 

 the parenchyma and the walls of the lateral vessels." 9 A 

 very brief description of the experiment performed by these 

 investigators will suffice to make the crucial part of the 

 results clear. The nemertean has a long section of body 

 in front of the mouth, consequently into which no part of 

 the intestinal canal extends. From this it follows that if 

 the animal be cut in two anterior to the mouth, the front 

 piece will be wholly devoid of digestive organs. Notwithstand- 

 ing this it was found that these gutless, mouthless pieces 



