288 



SCIENCE 



[N. S. Vol. XXXVIII. No. 974 



contacts affecting the nociceptors and oJ 

 the invisible contacts by those intangible 

 forces which affect the distance ceptors. 

 For example, each variation in speed of the 

 light-producing waves of ether causes a 

 specific reaction in the brain. For one 

 speed of ether waves the reaction is the 

 perception of the color blue; for another, 

 yellow ; for another, violet. Changes in the 

 speed of air waves meet with specific re- 

 sponse in the brain patterns tuned to re- 

 ceive impressions through the aural nerves, 

 and so we distinguish differences in sound 

 pitch. If we can realize the infijiite deli- 

 cacy of the mechanisms adapted to these 

 infinitesimal variations in the speed and 

 intensity of invisible and intangible stim- 

 uli, it will not be difficult to conceive the 

 variations of brain patterns which render 

 possible the specific responses to the coarser 

 contacts of visible environment. 



Each brain pattern is adapted for but 

 one type of motion, and so the specific 

 stimuli of the innumerable ceptors play 

 each upon their own brain patterns only. 

 In addition, each brain pattern can react 

 to stimuli applied only within certain lim- 

 its. Too bright a light blinds; too loud a 

 sound deafens. No mechanism is adapted 

 for waves of light above or below a certain 

 rate of speed, although this range varies in 

 different individuals and in different spe- 

 cies according to the training of the indi- 

 vidual and the need of the species. 



We have already referred to the fact 

 that there is no receptive mechanism 

 adapted to the stimuli from the X-ray, 

 from the high-speed bullet, from elec- 

 tricity. So, too, there are innumerable 

 forces in nature which can excite in man 

 no adaptive response, since there exist in 

 man no brain patterns tuned to their 

 waves, as in the ease of certain ethereal 

 and radioactive forces. 



On this mechanistic basis the emotions 



may be explained as activations of the en- 

 tire motor mechanism for fighting, for 

 escaping, for copulating. The sight of an 

 enemy stimulates in the brain those pat- 

 terns formed by the previous experiences 

 of the individual with that enemy, and also 

 the experiences of the race whenever an 

 enemy had to be met and overcome. These 

 many brain patterns in turn activate each 

 that part of the body through which lies 

 the path of its own adaptive response — 

 those parts including the special energizing 

 or activating organs. Laboratory experi- 

 ments show that in an animal driven 

 strongly by emotion the following changes 

 may be seen: (1) a mobilization of the 

 energy-giving compound in the brain cells, 

 evidenced by a primary increase of the 

 Nissl substance and a later disappearance 

 of this substance and the deterioration of 

 the cells; (2) increased output of epine- 

 phrin, of thyroid secretion, of glycogen 

 and an increase of the power of oxidation 

 in the muscles; (3) accelerated circulation 

 and respiration with increased body tem- 

 perature; (4) altered metabolism. All of 

 these are adaptations to increase the motor 

 efficiency of the mechanism. In addition 

 we find an inhibition of the functions of 

 every organ and tissue that consumes en- 

 ergy, but does not contribute directly to 

 motor efficiency. The mouth becomes dry ; 

 the gastric and pancreatic secretions are 

 lessened or are completely inhibited; peri- 

 staltic action stops. The obvious purpose 

 of all these activations and inhibitions is to 

 mass every atom of energy upon the mus- 

 cles that are conducting the defense or 

 attack. 



So strong is the influence of phylogen- 

 etic experience that though an enemy to- 

 day may not be met by actual physical 

 attack, yet the decks are cleared for action, 

 as it were, and the weapons made ready, 

 the body as a result being shaken and ex- 



