233 



duoed after injury,* Yet the chief factor in their production 

 ■belongs undouhtedly to the poisonous natter produced by the 

 (SYS) gall anlraals. Besides the factors which hypothetioally are t» 

 he considered in callus tissues, the action of some special 

 poison will have to he reckoned with, T/hen analysing the "gall- 

 stimuli"^, 



A comparisen of the ahove-narried tissue forms with the kat- 

 aplasmas already desorihed leads to new considerations, Isought 

 t^ hrlng forward proof thet kataplasmas correspond histolpgio- 

 a3jly In all essentials, often indeed in all details, vithi wound 

 tjl,ssues, (callus, wound-wood), Therefore the Interference pro- 

 oeedlng from the Infecting organisms rnd the conditions under 

 which the tissue oX the host plant is brought hy those inter- 

 ferences ai-e not forthwith to he put on an e<iuality vrlth the 

 or^es which, In coarse Injuries and mutilation of the plantt hody, 

 result In the formation of wound tlsste , Whenj- forexample, a 

 fungus grows in some plant tissue ond incites it to the f^rma- 

 tl,on of abnormal excresoenceB. corresponding in every way with 

 tl^ose produced after injury, the reason for their formation can 

 scarcely be caused by changed transpiratory conditions, ^.t any 

 rate, In many cases one can not speak of the ehemical action 

 of dead cytoplasm nor of any product of decomposition.- ai^d it 

 Is certainly not probable that changes take place in the ipechan- 

 leal action ef pressure and incite the grcvth of the abnormal 

 tissue in the kataplasmas produced by sucking parasites which 

 live superficially. (Hemiptera), The contact ef the inner 

 layers of tissue with atmospheric air should be taken intp con-» 

 sideration fts a contributing factor in the production of tbia 

 kind of Zoocecldia and Phytocecidia. Hence the question follows, 

 as to whether factors of different kinds can incite the formation 

 of similar kinds of tissues, or v/hrther perhaps injury and in- 

 fection make possible to the same extent the action of certain 

 factors, not found among those enumerated above and of wh(?se 

 quality we ean not as yet form any decision. 



Formative processes simpler than those named here seem 

 well suited for explaining more particularly thpt which w£^s 

 discussed above, 



I would call attention first of all to Kleb's observations 

 according to which it is possible to incite ^aucheria tubes to 

 the formation of zoospores by various kinds of i'^^^'^^J®^?^? ' ^ 

 Further I v/ould refer to the deformp.tion of fungus hypha^ and 

 the like describfd above (p, ); abnormal processes of gitowth 

 take^place'llthe concentration Of the «--oundi?f,f ^^i? a" 

 ges, if fluctuations in temperature become effective or if a 

 parAsite in the interior of the cell, robs i* ?* Pjrt of Its 

 ^tritive substances and so forth. We can either ^^sume in 

 relation to the question as to effective fJJ*?^^. *^* ^J^^^^Sfc 

 conditions of different kinds ^-^^^J^i^Jf *^?i*^ *Sonds fo un~ 

 the same effect in the cell, and that the cell J||J^^^J^ J° ^?he i:>- 

 like stimuli with the same reaction.- or ^^^* • ^J^^^^f^i^l'^conRic! - 

 diversity, external factors directly accessible for our consic 



eration aAd measurement result in the same ^f ^i*^??^',^^J°^ ,^,^ 

 would come under consideration only as causes ^f f l"ulation ...i 

 bring about the phenomena of reaction studied here, ii '^ 

 asce?tain the active factors, we mast S^^^-^Pj^e fact that be 

 ^r'4) tween the change in factors proved m ohe experiment ^am^Tjne^ ^ 



^ Compare also statement be^ow under 5, 



