METABOLIC CHANGES 



609 



of mucopolysaccharides in the connective tissues decreases, and similarly, the 

 amount of calcium in broken bones. The water-content of the tissues increases 

 (Paul et al., 1945) and there are probably significant changes in most metabolic 

 processes. These trends are all reversed in the P-phase. 



Systemic changes have been little studied in animals with high powers of regen- 



0.30 



Left limb 

 5 6 7 



0.25 



0.20- 



3 4 5 6 7 



Sequence of acts of regeneration 

 (Right limb) 



Fig. 4. Changes in gross regener- 

 ation-rate per day of a pair of 

 limbs of Asellus, regenerating 

 repeatedly, the right limb (O) one 

 repetition ahead of the left (□). 

 The rate declines at first but re- 

 covers during further repetitions 

 and finally declines progressively 

 due to exhaustion, or to old age. 

 The fluctuations for the left limb 

 are forced into partial synchroni- 

 sation with those for the right and 

 are somewhat damped. (From 

 results of Needham, 1949b). 



eration of external organs, but it seems probable (Needham, 1955) that there 

 is a systemic nitrogen-flow comparable to that found in mammals, in the R-phase of 

 liver-regeneration (Friedgood et al., 1950), and of skin- and bone-healing (Crofts 

 and Peters, 1945; Munro and Cummings, 1948; Guthbertson, 1954; Campbell 

 et al., 1954). This excess urinary nitrogen does not come mainly from local demoli- 

 tion, or from dedifferentiation which involves the destruction of extracellular 

 protein, and of course urinary nitrogen represents protein lost to the body. It is 

 possible therefore that these systemic events are not related specifically to the 

 processes of regeneration, but rather to a non-specific "general alarm reaction" 

 or "general adaptation syndrome" (GAS) following "stress" of any kind, traumatic 

 or otherwise (Selye, 1946, 1948, 1955). 



However, many components of the GAS resemble, or are consistent with, the 

 local changes. There is an increase in acidity of the blood due, in part at least, 

 to lactic acid and to increased glycolysis (Green and Stonor, 1954). Water is 

 retained by the body and movements of Na and K between cells and plasma may 

 be both local and general. The GAS, like the local changes of the R-phase of 

 regeneration, is in general regressive and catabolic in nature, and body-growth 

 is inhibited during the GAS, as it is in the early stages of regeneration in the stick 

 insect (p. 638). The changes associated with the GAS are subsequently reversed, 

 just as the local changes. No doubt stresses of all kinds cause damage, often dissem- 

 inated and perhaps inconspicuous morphologically, so that the sharp localisa- 

 tion of regeneration is only a special case. Selye (1955) in fact refers to the local 



Literature p. 64rj 



