242 



(282);yhich withdraw v/ater,- thus reducing the turgor of the cells, 

 increasing the concentration of their contents and so the os- 

 motic pressure. The hairs grow chiefly in thickness, Instead 

 of continuing their normal growth in length, Reinhardt ob- 

 served the same phenomena (se© above) in fungus hyphae. Changes 

 in concentration and composition of the surrounding medium as 

 well as fluctuations in temperature have called forth the same 

 deformations. In both aases -we ma;? ventiiye to explain the ab- 

 normal forms by fluotuatiohs in turgor and osmotic pressure. 

 In Just this connection in mjr opinion belong the Vauoheria. galls 

 of Uotommata, the involution forms of bacteria find others. 



There is a need of & closer testing of the question as to 

 whethet abnormal processes of growth in etiolated plants, the 

 phenomena of "starvation-etiolation" and others, may be ex- ' 



, plained in the same way, - and further whether hypertrophies, 



I produced after poisoning (gall hypertrophies), may in part at 



least be iinderatood to be the result pf phyticnl changes in the 

 cell^mlcfbbsm6s, It may indeed "bg possible that substances are 

 supplied to the infected plant cells by the parasite, which act 

 on th© coll life to the host plant less through their chemical 

 qualities than their physical characteristics and may perhaps 

 cause an abnormally high osmotic pressure within the infected 

 cells. This poijt also will have to be considered in a future 



*■ analysis of the "gall-stimulus". Let us remember further that 



any abnormal absorption of WQter reduces the concentration v'ith- 

 In the cell, ©nd therefore its osmotic pressure, but that amal- 

 ogous changes in osmotic pressure are produced not only by the 

 absorption, or the giving off of v;ater, but also by fluctuations 

 in temperature and by chamical transpositions within the cell, 

 in which substances osraotically effective are converted into 

 ineffective ones, or osmotically ineffective substancds are 



j changed to effective ones. As is shown, a varying connection 



exists bet?/een the osmotic pressure within the cell and the ex- 

 ternal conditions of life, A wide fieM of work lies open here 

 for future ihvestigation. Por the present we must limit our- 

 selves to the mention of new questions. 



The diffusion currents in the cell body are closely 

 connected with the osmotic pressure wihhin the cell, these 

 I will mention briefly. 



The growth of a crystal in its mother solution undoubt- 

 edly leads to some changes in the concentrr.tion of the 

 solution immediately surrounding the crj'-stal. The changes 

 in concentration for their part result in diffusion-cur- 

 fents which are definitely directed. DiffeisAnces in the 

 processes of diffusion and therefore in the conditions 

 necessary for the continuance of growth on the different 

 parts of the crystal will apparently be produced so much 

 the sooner, the greater the amount of the surface of the 

 srvstal here concerned. The fact that crystals of definite 

 substances usually continue their "normal" growth only tona 

 certain size,- and then grow "abnormally",- wakes it possi- 

 ble to conclude without doubt as to unequal conditions of 

 crystallization on the different parts of the crystal, and 

 we may conceive of some minute "disturbances" in the c ....ri"> 

 of the diffusion currents. 



(283) These diffusion currents must 'ae produced in the living 



cells just as in the crystal -mot heg*- solution, if a crystal 

 or a conglomerate of crystals is produced anj'where in the 



