§5.112 RESPIRATION 179 



16 per cent; but when the glands are stored for some time before 

 making alcoholic extracts, it is doubtful whether the extracts 

 contain a substance that is normally released into the blood 

 (Edwards, 1950). Control injections of saline and of muscle 

 extracts did give negative results ; but extracts of other parts of the 

 eyestalk or even of whole eyestalks were not tested in this case 

 (Fig. 5-5). 



When such extracts are made and injected into eyestalkless 

 crabs, such as Uca, oxygen consumption is reduced to nearly 

 normal (Fig. 5-6). 



Removal of sinus glands from Astacus (Frost et al., 1951) has 

 practically the same effect as a mock operation in which the glands 

 are exposed but not removed, whereas removal of the whole 

 eyestalk has a much greater effect (Table 19). This last experiment 



Table 19. Changes in oxygen consumption in astacus, following 

 sinus gland or eyestalk removal 



Individual values for oxygen consumption in cmVhr/lOOg body weight 

 (from Frost et al. 1951). 



SPECIMEN 



Pre-operative values 

 After mock operation 

 After sinus gland removal 

 After eyestalk removal 



3-06 4-56 4-77 5-57 



5-13 5-33 617 



3-02 5-38 6-26 



5-16 7-77 



was not well controlled, but in Camharus the removal of both 

 antennae, which would be an operation of comparable severity to 

 eyestalk removal, had no effect upon oxygen consumption. 

 ' Bliss (1953) interprets similar but more detailed experiments 

 to mean that although the respiration-inhibiting hormone is 

 stored in the sinus gland, and can therefore be supplied by 

 injected extracts, its source is in the ganglionic-X-organ, which 

 supplies sufficient hormone for control of respiration after removal 

 of the sinus glands. Eventually, after removal of both sinus glands. 



