THE DEEPENING OF PHYSIOLOGY. 309 



fresh bee's brain in the morning and the fatigued 

 bee's brain in the evening, or the results of others 

 who have investigated the fatigue-conditions in vari- 

 ous nerve-centres, we find an impressive set of facts, 

 showing how fatigued nerve-cells pass into a state of 

 collapse from which recovery may be rapid, long- 

 delayed, or impossible. That the enquiry has its 

 bearings on mis-education, over-pressure, strain, and 

 worry, and the like is obvious enough. But as to 

 the particular components of the neuron on which 

 the fatigue-state most essentially depends we are 

 still in doubt. 



We have been particularly indebted in this sec- 

 tion to a lecture by Prof. Max Verworn * who sup- 

 ports the neuron-theory enthusiastically, and we 

 should also refer to another by Hoche,f who main- 

 tains that the functional unity of the neuron must 

 be recognised, though its histological unity is in adult 

 animals undemonstrable. 



" The kernel of the neuron-theory is that the body 

 of the ganglion-cell with its nerve-fibre and its den- 

 drites is a cellular unity. . . . The anatomical and 

 physiological investigations of the last decenninm have 

 not been able to shake this. . . . "Whether the individ- 

 ual neurons are merely connected by contact, or in 

 many cases are continuous by the anastomoses of fibrils 

 or protoplasmic concrescence, is a minor question, affect- 

 ing the neuron-theory not more than the fact of inter- 

 cellular bridges affects the cell-theory. . . . The con- 

 ception of the neuron stands, unless it can be shown 

 that what is regarded as a cellular unity is really com- 

 posed of several cells. . . . The neuron is varied in its 



* Max Verwovn, Das Neuron in Anatomie und Physiologic: 

 Jena, 1900, p. 54. 



f A. Hoche, Die Neuronen-lehre und Hire Gegner : Berlin, 

 1899, 



