24? 



The lack of unanimity of theee authors is doubtless ejg- 

 plained by the present lack of clearness in the interrogation 

 of the phenomena. 



It is indeed evident that even unusual hyperplasias like ' 

 normal pnrts of plants are composed of cells. The question is, 

 hov/ must the cells he constituted if they may he termed "nev;" 

 kilnds of cells. Evidently the investigators here nan© d hr.ve 

 ans^CB^d this question differently and thus have arrived at 

 different results, In drawing their conclusions. YIe vill first 

 of all he obliged to understand clearly the preliminary ques- 

 tion, before taking up once more the oft discussed problem, 



"Uer;" qualities, thart is, ones which vary from the normal, 

 may be expected to arise In different ways. The conditions of 

 size may be "new", or the forms, or finally the inner structure 

 of the cells. We will therefore have to compare abnormal cells 

 V7ith normal ones, as to size, form and inner structure. 



(288) 1. Size of the Oella 



Aside from the individual unbranched latex tubes, which" 

 seem to be distinguished (theoretically) by unlimited grovrth, 

 each kind of cell in plants forming tissues possesses a definite 

 size, which is attained early,- and fluctuates only within 

 narrow limits in the individual species. 



We have seen above that cells of very different tissue 

 forms may hjrper trophy; 4. b, may enlarge their volume beyond 

 a normal amounts The question must still be discussed, as to 

 whether the largest cells, to be found in a norme.lly developed 

 plant body, may not perhaps give a maximum cell volume valicl 

 for the species concerned, beyond which no cell of any tissue' 

 whatever of that species can hypertrophjT-,- in s^ch a way that, 

 so far as cell size is concerned, the plant can furnish nothing 

 which could not be attained by it also under normal conditions . 



The conditions in primitive organisms are most easily s-.iir- 

 veyed., v/hich, under normal conditions, develop cells of only 

 one size , such as, for instance, bacteria. The often gigantic 

 Involution forms of the sohizomycetes prove forthwith ttet, 

 under abnormal conditions, cell-growth can far exceed t ha normal 

 standard while no definite limits ^;ould be recognmzable, 



p The conditions in higher plants are just the same. In 

 them too we find no support for the aseiunption that a limiting 

 volume, determined in the plant body, may be determinative for 

 cells grown under abnormal conditions. Figure 12:}., at the leit, 

 illustrates some libriform fibres and pieces of ducts of Quercuffi 

 at th^ right some cells of the oak g^ll produced by Spathegaster 

 baccarum . Ho further explanation is needed to show that abnor- 

 mal cells can far exceed the volume of normal ones. 



Cells of a tissue under abnormal conditions frequently 

 become appreciably larger than corresponding normal ones; they 

 may more rarely occur appreciably smaller. . However, no fixed 

 (289) bou.iIr,ries exist also for this lower limit. I will call at.oii-^ 



tlon later to the dwarf Desnidiaceae described on page 27, to the 

 ducts of hypoplastically developed plants which have abnorme-lly 

 narrow lumina and to mycelial threads with excessively napeow 

 lumina, which may be fo\ind produced in solutions poor in nutri- 

 tive substances. 



