£88 



If the cells are ox^er "-abundantly provided vrith those substances, 

 many processes of gro"C7th and formation may in oner/ay or another 

 be continued beyond the norraal standard, Hovrever, it v.?jLll 

 scarcely be possible to decide in a single case as to whether 

 the nutritive substances act as stimulation causes, tr whether 

 the cells are not rather given the oapaqity for"TeaetiQn by 

 these substances, in order to react, In the way described, to 

 any stimulation causes V7hich aS yet have been discovered. 



In some cases we nr.y nov conclude that most probably the 

 supplying of nutritive substances hag only some "preparatory" 

 action. Rotwc has shorjn thr.t the hypertrophy of activity in man 

 and animals can not be a reaction to functional hyperaemla 

 (and the supplying of nutritive substances connected with It) 

 but ls,to be understood as a specific effect of the increased 

 demand*, The same conditions exist for the activity hyperplasias 

 of mechanical plant tissues described above. The supplying of 

 nutritive substances, \7hioh certainly precedes their formation, 

 , apparently only makes the tissues capable of reacting in the 

 8bove described way to stimuli of a definite kind;- in the present 

 ease to mechanical strain and pressure. The actual freeing 

 momentum does not lie in the supplying of nutritive substances 

 but in the action of raeohanioal factors;- hence the necessity of 

 mentioning activity hjTierplasiaS under I, Xf "^e find that def- 

 inite formcitioh* of tissue occur after the supplying pf nutritive 

 substances, it r/111 be necessary, even whdn Jio other fnctors may 

 be found to be the cause of stimulation, t« think of the possi- 

 bility th§t the supplying of nutritive substances is effective 

 only as a preparation,- not as a setting free,- and that tJie i 

 factors TThich do set free are atill unknown. I will return at 

 once to this point. 



The action of oxygen and water is exclusively preparatory. 

 Among the cases, which are of interest to us, not one can be 

 found in which a freeing stimulus proceeds from the supplying of 

 oxygen*. The numerous cases in which the supplying of water acts 

 releasingly v/lll be discussed in another sub-division because 

 (279) in them apparently the v/ater does not act as a nutritive sub- 

 stance, being effective only because of its physical qualities, 

 not at all because of its chemical ones. 



The conditions are much clearer when the effective sub- 

 stances are not nutritive ones, but are poisons , which incite 

 the cells to some activity without themselves fiirnishing any 

 building material. We may assume that no "preparatory" effect 

 proceeds from them, but a freeing one. 



^ Roux, per auchtende Kampf der Telle in Organisms, 

 1881. C?es, Abhandl, Bd, 1, p. 315 ff. 



^ That, under certain conditions, the supply of oxygen 

 may also bring into existence directly or indirectly, r|l«/veing 

 effects is shotm by JJatzuschita^s investigations on anae^rfW 

 bacteria, which f^tm spores under the influence of o^Qrgen, (Zur 

 Phys. der Sporenbildung d. Bacillen etc, mssertation Halle, 

 1902. Arch. f. Hyg.» 1902, Bd. XLIII, p. 267). 



