176 The Unitij of the Organism 



understood to imply that the resemblance is not sufficiently 

 close to make them indeed such tubules. 



On the matter of organ production by tissues separated 

 from the body, Burrows has given us a decisive statement. 

 *'Such growing cells," he says, "from an isolated piece of 

 tissue have at no time shown evidence of grouping in a form 

 comparable to organ formation in the body." ^' 



Some experimenters appear to have clearly seen the im- 

 portance of this limitation of ])ower of the tissues, and on 

 this account have taken rather strong grounds against call- 

 ing the preparations "cultures." J. Jolly in particular 

 has his eyes wide open toward the phenomena, though pos- 

 sibly some details of his criticisms are overwrought. He 

 says, "In certain tissues in vitro it appears possible for cel- 

 lular nmltiplication to continue for some time, that much is 

 true; but between this last effort of certain cells and a 

 'culture' — a development continued and progressive — there 

 is a gap, which may be filled up some day. For the present, 

 it is an abuse of language to attach the name 'cultures' to 

 the results obtained." ^^ And the author thinks true de- 

 velopment of kidney tubules is not proved by Carrel and 

 Burrows. 



Denial of development in a strict sense is made also by 

 A. Dilger : "On the basis of this critique and of his own 

 investigations, the author nnist emphatically deny that in 

 the case of cultures of fragments of the mature organs of 

 warm-blooded animals any genuine growth takes place in 

 the sense of an organic formation. In this essential the 

 author would adopt the view of Jolly, that the Carrel-Bur- 

 rows experiment indeed demonstrates a survival and physio- 

 logical functioning of tissue fragments, but has nothing to 

 do with their growth." ^^ 



It may be unprofitable to spend time on the question of 

 what name should be applied to these imique preparations, 

 further than to insist that the name settled upon shall not 



