50 PHYSIOLOGY CHAP. 



Cases of survival of the animal after the excision of both 

 capsules are rare, and must be explained either by incomplete 

 extirpation or by the existence of accessory suprarenals 

 (Szymonowicz). The most important points in the rich modern 

 literature of the physiology of the capsules may be briefly 

 summarised. 



The methodical research undertaken by Abelous and Langlois 

 (1891-92) on the frog showed that 



(a) Complete destruction of the capsule by the method of 

 cauterisation inevitably causes death (after 12-13 days in winter, 

 after 48 hours in summer) with symptoms of progressive paralysis, 

 which commences in the lower limbs (24-30 hours after the 

 operation) and subsequently becomes general and produces death. 



(6) General paralysis follows more rapidly if the frog is 

 frequently excited after the operation, so as to provoke muscular 

 movements. 



(c) Destruction of one capsule alone produces no morbid effects 

 in the frog : complete destruction of one capsule and of the greater 

 part of the other determines death in most cases, but after a 

 longer time. Death is then invariably preceded by convulsions 

 and dyspnoea. 



(d) On grafting the capsules of a normal frog into the dorsal 

 sac of the decapsulated frog, the survival period of the latter is 

 doubled. On dissection, the graft is found not to have taken, the 

 capsules being reduced in volume and decolorised. Injection of a 

 watery suprarenal extract results in a less marked prolongation 

 of life. 



(e) Intravenous or subcutaneous injection of the blood of a 

 moribund, decapsulated frog into a frog that has been recently 

 operated on, causes rapid paralysis and death. The same injec- 

 tion into a normal frog produces only slight and transitory 

 disturbances. 



(/) If immediately after destroying the capsules in a frog the 

 sciatic is exposed, and a thread tied round the leg at a lower 

 point, by Bernard's method, while the blood from a moribund 

 decapsulated frog is injected under the skin, then at a certain 

 stage of intoxication (3 hours after injection) the most powerful 

 induction shocks have no effect on the sciatic of the free limb, 

 while a weak current easily borne by the tongue produces 

 energetic contractions from the sciatic of the ligatured limb. 

 Direct application to the muscles of either leg produces contrac- 

 tions, which are, however, stronger in the tied than in the free 

 limb. 



From these facts Abelous and Langlois concluded that death 

 from removal of the capsules is due to the accumulation in the 

 blood of one or more toxic curarising substances, i.e. such as act 

 like curare on the end-plates of the motor spinal nerves, and in a 



