380 R. R. BENSLEY 



When we begin to search in Laguesse's articles for the evidence 

 of transformation beyond the fact of continuity, we find that 

 such evidence is very meager and not always consistent. For 

 example, in one place he describes the A cells of the islets as 

 transitional cells, and in his late article on the human pancreas 

 describes another case of direct transformation of acinus cells 

 into B cells with an intermediate type which is similar in some 

 respects to both. 



In his general resume of the literature ('06- '08) he gives in 

 figs. 67 and 68, and in the accompanying text, illustrations and 

 descriptions of the growth of an islet in the human pancreas at 

 the expense of neighboring acini with which it is continuous. In 

 these figures he depicts, around the islet, on each side, groups of 

 cells which connect it with the surrounding acini, which, he says, 

 possess intermediate characters. I have examined these figures 

 carefully, and studied his description, but have failed to find any 

 evidence that these cells are not, as they seem, in part duct cells, 

 and in part acinus cells cut tangentially. As the material was 

 fixed in alcohol any fine cytologic differentiation was impossible. 

 Similarly, fig. 69 in the same article is, it is true, an abnormal 

 acinus, but the evidence that it has been derived from an islet is 

 wholly lacking. 



That the fact of continuity, and of intermixture of the two tis- 

 sues has had great influence in Laguesse's mind is indicated by the 

 following extract from his discussion of these conditions in 

 ophidians : 



De deux choses Tune, ou cet engrenement, ce melange est I'indice 

 d'une transformation de Tun des deux tissus en I'autre, ou bien il faut 

 le supposer persistant depuis Tepoque lointaine du developpement em- 

 bryonnaire. Peut-on encore admettre cette derniere supposition en 

 ayant sous les yeux les figures pr^cddemment donnees (figs. 63 and 65 

 showing continuity)? Pour nous, cela nous est impossible. Nous 

 avons une toute autre conception de la vie ; la vie, c'est le mouvement ; 

 la vie d'un groupe celluleire c'est le changement incessant de sa forme 

 et la renouvellement de ses molecules. 



Even if we admit this conception of cell life it is a far cry from 

 the simple renewal of the cell's molecules to the complete transfor- 

 mation of it into another type. One cannot help wondering how- 



