243 



cells, or if any soluble substance is gradually cr-rried 

 over into an insoluble eonpound. Therefore, for example, 

 in the construction of a starch grain, in the growth of a 

 membrane etc. , ve may nev assume that the course of this 

 process of growth becomes irregular when different parts 

 of the growing form are placed under dissimilar conditions 

 of gro'^'th, by disturbances in the regulnr process of diffu- 

 sion. Y7ithout doubt disturbances of this kind occur so 

 much trhe more easily and cam become so nuch the more con- 

 spicuous, the larger the grovTlng forms are. 



It is a notenorthy fact thct even in the organic king- 

 dom there exists some connection between abnormal size and 

 abnormal form, Figure 120 gives at B some abnormal giant 

 starch grains from the qorrelation-heteroplasmas discussed 

 above (p. 152), vrhich Voohting found In the form of "leaf 

 tubers" in Oxa lls orassloaulis . The abnormr.l grains (B) 

 appear, beslTe the simple normjil ones (A) as bizarre as is 

 possible. "All sho-7 peculiar appendages, some short and 

 knob-like, tthers longer, sometimes Iftng and straight, or 

 again bent like hoods", iSt times lrregu]r r humps are pro- 

 duced, -hich can fill whole cells, We do not kno^; why 

 starch grains should be oorae l a rg er in the above-named 

 (284) abnormal tissues, then unrler normal conditions, 5?heir ab- 

 normal form is caused, I expect, at least in pert, by the 

 above discussed differences in the conditions of growth . 



In A consideration of entire cells, we also often find 

 abnormp.1 forms associated with abnormp^l size, A well-kno\7n 

 wxample of this is furnished by the involution forms of 

 bacteria, among .;hioh are found brr.nclB d forms, lying next 

 to vesicular or spindle-like ones. The latter are evidently 

 produced by differences in the conditions of gro'.rth in dif- 

 ferent parts of the ce3.1 membrane, and by the unlike dls- 

 tribiitlon of substances. The branching will arise ceteris 

 paribus on the places "preferred" - those better provided 

 with building nBterial. The larger the cells, the more 

 easily are produced the described differences in the In- 

 tra-cellular distribution of substances through disturbance 

 of the diffusion currents, 



B. On Reaction to Stimuli 



The preceding chapters have contained more detr.iled reports 

 on the reaction to stimuli of cells and tissues in so far as 

 they consist of processes of grov-th and differentiation. Only 

 a fev7 general remarks remain to be added to this point. 



In the normal course of life of a cell, wb find that cell 

 division regularly follows cell growth In such a v?ay that nu- 

 clear division and the formation of cross walls takes place as 

 soon as the definite cell size is reached. Evidently, during 

 the growth of the cell, some physical conditions or some chemi- 

 cal substances are produced, '.vhich incite the cell body to di- 

 vision. In this process we ore concerned with the effects of 

 stimulation action and indeed of interrtPl stimulation, the ef- 

 fective factors being produced >y the activity of the cell it- 

 self. By means of innu^^erahle examples, pathological plant 



In many, processes of coalescence alao may possibly be 

 at work. 



