CHAPTER IV 



THE GENERAL EFFECT OF STIMULATION 



Contents: Various examples of the effects of stimulation. Metabolism 

 of rest and metabolism of stimulation. Metabolic equilibrium. Dis- 

 turbances of equilibrium by stimuli. Quantitative and qualitative 

 alterations of the metabolism of rest under the influence of stimuli. 

 Excitation and depression. Specific energy of living substance. 

 Qualitative alterations of the specific metabolism and their relations 

 to pathology. Functional and cytoplastic stimuli. Relations of the 

 cytoplastic effects of stimuli to the functional. Hypertrophy of 

 activity and atrophy of inactivity. Metabolic alterations during 

 growth of the cell. Primary and secondary effects of stimulation. 

 Scheme of effects of stimulation. 



In the foregoing lectures we have had occasion to touch more 

 or less often on the subject of the effects of the stimuli. This 

 was the case, however, only when it appeared necessary to obtain 

 a systematic knowledge of the stimuli and the differentiation of 

 the individual factors. We will now proceed to consider the 

 effect of stimulation in a more systematic manner. The condi- 

 tional method of observation, however, will remain our guide. 



We have already pointed out the relations between the con- 

 ception of stimulation and that of vital conditions, now we will 

 consider that of the effect of stimulation with that of vital pro- 

 cesses. Nevertheless, the effect of stimulation being a manifesta- 

 tion of the vital process is not, therefore, in opposition to the latter 

 as such. Hence the question presents itself as to the connections 

 between vital process and the effect of stimulation. 



When we study the motile flagellate infusorium Peranema 

 swimming undisturbed in water, we observe that the swimming 

 movements are absolutely regular in character. The elongated 

 cell body remains unaltered in shape. The long flagellum is 

 extended in a perfectly straight line in the axis of the body and 



