Chapter X 

 MORPHOGENESIS 



It was suggested at the beginning of this volume 

 that the technique of cultivating excised tissues 

 had its chief raison d'etre and gave its greatest 

 promise in the study of the origins of form and 

 function, that is, in problems of morphogenesis. 

 Harrison 's original problem which led to the first 

 in vitro cultivation of animal cells — whether the 

 nerve fibrils originate in situ from the innervated 

 cells or their products or whether they originate 

 ab extra, by growth from the distant ganglia — was 

 a morphogenetic problem. So was Robbins ' orig- 

 inal problem — whether the root was dependent on 

 the leafy portions of the plant for anything more 

 than its basic carbohydrate nutrition. So like- 

 wise was the problem — what was the nature of the 

 stimulus by which crown gall organisms or their 

 products induce abnormal proliferation of the 

 host cells — which led the author of this volume to 

 undertake the development of a plant tissue cul- 

 ture technique (White, 1931, 32). The number of 

 problems which have been attacked to date by 

 means of this technique is not large. But the 



