1 82 Journal of Agricultural Research voi. vi, no. 4 



Rapidly developing young tissues seem to be necessary. Here again, 

 a changed stimulus has produced a more embryonic and primitive 

 condition, as shown by the appearance of these shoots. It is a patholog- 

 ical phenomenon, but one of more than passing interest, for, unless I am 

 much mistaken, it has wide physiological and pathological bearings. 

 It is another proof that the immature cell wherever it is located carries 

 the inheritance of the whole organism, and that what it will finally 

 become, as it matures, depends on the stimuli withheld from it or applied 

 to it. In other words,' it is so much evidence that any young cell may 

 become a totipotent cell if it is subjected to the proper stimulus, and this 

 stimulus may be either physiological, resulting in a normal structure, 

 as when the top of a plant is removed and a new top grows in its place 

 out of so-called adventitious buds (regeneration phenomena), or patho- 

 logical, resulting in an embryonic teratoma, as when a tumor-producing 

 schizomycete is introduced into sensitive growing tissues. 



PLATE XVIII 



Teratoid crowngalls produced in Pelargonium spp. by inoculating Bacterium 

 tumefaciens (hop organism through sunflower) into upper leaf axils on January 13, 

 1916. Photographed at the end of 74 days. At X the top of the shoot bearing five 

 or six leaves was removed to show the tumor more distinctly. All of the leafy shoots 

 here shown and many others too small to be seen distinctly in the photograph are 

 outgrowths from the tumor, which also bears red abortive flower anlage. The upper 

 shoot (L) was also flattened and fasciated (several shoots fused together) and the front 

 leaves (P P) were turning yellow and dying. 



