ABNORMALITIES OF NEURAL FUNCTION IN THE PRESENCE OF INADEQUATE NUTRITION 



l8 95 



children, making them dull and apathetic. Carothers 

 (36, p. 111) believes that the arrest of mental develop- 

 ment at the age of 2 to 4 years is unlikely to be com- 

 pletely remedied in later years. Even children who 

 are not severely ill are remarkably silent and still 

 (275, p. 100). They seem to have lost all normal 

 curiosity and, in advanced stages of the disease, they 

 are hopelessly apathetic, showing only the responses 

 of resentment and pain. The behavior is considered 

 as the best single guide to the degree of severity of the 

 disease. As to neuropathology, cerebral edema and 

 congestion is frequent, but the brain has not been 

 studied in detail and the histological counterpart, if 

 any, of the mental changes is not known (275, p. 155). 



DEHYDRATION 



Water deprivation, much as the deprivation of 

 calories and some essential nutrients, markedly 

 affects behavior long before any clear changes take 

 place in the capacity of the nervous system to function 

 normally. Thus general activity is substantially ele- 

 vated when rats are deprived of water, with food 

 available ad libitum (73). 



According to Morgulis (182), severeh dehydrated 

 animals have hyperemic eh. nines in the brain and 

 spinal cord, but on the basis of available information 

 it is not easy to determine a causal relationship be- 

 tween dehydration and the nervous alterations 

 Although water is held in the nervous substance with 

 great tenacity, even when the rest of the both is 

 dehydrated (J43, p. 34), dehydration produces a 

 variety of important functional alterations in the 

 body, affecting the composition and the distribution 

 of body fluids, the circulation, and temperature regu- 

 lation, which may cause the neural manifestations 

 seen in this state. 



The descriptions of signs and symptoms of dehydra 

 tion in man are based on observations in children 

 suffering from severe diarrhea and in patients with 

 cholera and extensive burns, as well as in men lost in 

 the desert and in shipwreck survivors. In modern 

 times the work of Adolph and his co-workers provided 

 valuable information on this problem (3). 



McGee (163) distinguished five periods (clamorous, 

 cotton-mouth, swollen tongue, shriveled tongue and 

 blood sweat) corresponding to different degrees of 

 dehydration resulting from a water deficit of 2 to 20 

 per cent of the initial body weight. Besides thirst, 

 which is the first and obvious subjective symptom 

 of dehydration, changes in behavior — apathy. 



impatience and sleepiness — appear earlv. Tempera- 

 mental types are exaggerated; "serious people be- 

 came positively sombre while others, normally cheer- 

 ful, exhibited a somewhat hollow vivacity" (23). The 

 subjects were capable of performing estimations and 

 computations but their power to concentrate was 

 impaired. 



When the degree of dehydration exceeds 10 per 

 cent loss of the original body weight (corresponding 

 to the last three stages of McGee's classification), 

 more serious manifestations develop, including 

 delirium, spasticity and inability to walk. Perception 

 is greatly impaired, and deafness and blindness m.u 

 develop. In the terminal stages stupor and uncon- 

 sciousness dominate the clinical picture. 



I nder conditions of shipwreck an inadequate stock 

 of drinking water constitutes, alter cold, the most 

 distressing and dangerous hardship (431. Thirst, the 

 dominant subjective symptom of dehydration, in- 

 creases in intensity until it may completely over- 

 shadow tin' discomforts of hunger, cold, pain of 

 wounds or sores, and fatigue. Severe dehydration, 

 frequentl) complicated l>v sea-water poisoning, re- 

 sults in blurred consciousness, illusions and hallucina- 

 tions, and, finally, in delirium and death. Analysis of 

 reports conccrninu; shipwrecked seamen indicates that 

 the effects of drinking sea water are almost invariably 

 disastrous (160). 



MINER vi s 



Minerals air required bv the nervous sv^trm princi- 

 pally for a) regulation of excitability (Ca, Mg, Na, 

 K), />) activation of enzyme sv stems (Mg, Mm, and 

 1 1 maintenance of structure (Cu). Present information 

 on electrolytes and nervous excitability and conduc- 

 tion was summarized by Keynes & Lewis (131). 

 Recent work has extended our knowledge concerning 

 the role of calcium and magnesium ions in neuro- 

 muscular transmission with special reference to 

 acetylcholine release (52, 53). Similar studies have 

 been made on the perfused sympathetic ganglion 

 (54, f>8, it 7). 



Sodium Chloride 



Heat cramps are well known as a symptom of salt 

 deficiency and their prevention by administration of 

 salt is firmly established (57, p. 82); but our under- 

 standing of the etiology is still incomplete. In man 

 lassitude and apathy are also produced (155, p. 40). 



