H. W. MAGOUN 7 



subjective impressions during induction of chloroform anaesthesia for 

 dental extraction, and concluded : 'This degradation of consciousness by 

 chloroform, abolishing fnst the higher faculties and descending gradually 

 to the lowest, may be considered as rcversnig that ascending genesis of 

 consciousness which has taken place in the course of evolution; and the 

 stages of descent may be taken as showing in opposite order the stages of 

 ascent.' 



"What is the implication oi this law as applying to different grades of 

 men?' Spencer asked. And answered, 'It is that those having well developed 

 nervous systems will display a relatively marked premeditation, a greater 

 tendency to suspense of judgment and an earlier modification of judg- 

 ments that have been formed. Those having nervous systems less developed 

 will be prone to premature conclusions that arc difficult to change. 

 Unlikeness of this kind appears when we contrast the larger with the 

 smaller brained races, when, from the comparatively judicial intellect of 

 the civilized man, we pass to that of the uncivilized man, sudden in its 

 inferences, incapable of balancing evidence and adhering obstinately to 

 first impressions.' Tliough Spencer's association with the female sex was 

 limited, he nevertheless felt qualified 'to observe a difference similar in 

 kind but smaller in degree between the modes of thought of men and 

 women; for women are more quick to draw conclusions and retain more 

 pertinaciously beliefs once formed'. 



Returning to the problem 'of how such higher co-ordinations are 

 evolved out of lower ones and how the structure of the nervous system 

 becomes progressively complicated', Spencer proposed the interpolation 

 of new plexuses of fibres and cells between those originally existing. In 

 diagrammatic sketches, apparently of an invertebrate ganglion, Spencer 

 distinguished (Fig. 2,) 'a nervous centre to which afferent fibres bring 

 all order of peripheral feelings, and from which efferent fibres carry 

 to muscle the stimuli producing their appropriately combined contrac- 

 tions'. If a part of the co-ordinating plexus (A) 'takes on a relatively greater 

 development in answer to new adjustments which environing conditions 

 furnish, we may expect one part of this region (a) to become protruberant, 

 as at A". Because space within the plexus was already pre-empted, 'the 

 interpolated plexus, which effects indirect co-ordination, must be super- 

 imposed [Fig. 2, A' above; d, below], and the co-ordinating discharges 

 must take roundabout courses as shown by the arrow. Little by little, there 

 is an enlargement of the superior co-ordinating centre by the interpolation 

 of new co-ordinating plexuses at its periphery' (Fig. 2, e, f, g, below). 



With the publication of Darwin's Origin of Species, Spencer gave some 



