448 PHYSIOLOGY CHAP. 



adult, Wertheimer (in 1886) endeavoured in France to repeat 

 the same experiments on adult animals by prolonging artificial 

 respiration for f-2 hours after section of the bulb, in order to give 

 time for the supposed traumatic inhibition to pass off. He 

 observed that at the close of artificial respiration the animals 

 made certain movements of the thorax, abdomen, and limbs, which 

 produced a kind of pulmonary ventilation, and kept them alive for 

 a considerable time, even in some cases for three-quarters of an 

 hour. 



On the whole, no definite conclusions as to the independence 

 . of the spinal respiratory functions from the bulb can be deduced 

 from these experiments. There is no proof that the movements of 

 thorax and abdomen observed under the above conditions after 

 division of the bulb, are co-ordinated like normal inspirations and 

 expirations ; in fact, it appears from Wertheimer's own observations 

 that they are irregular and inco-ordinate. Often they are simple 

 active abdominal expirations, followed by passive inspirations ; at 

 other times the inspirations are associated with repeated expira- 

 tions, which cancel their mechanical effects, and look like double 

 or triple inspirations. Very frequently the thoracic and abdominal 

 movements are associated with other movements of the limbs, tail, 

 and vertebral column, due to spread of excitation from the spinal 

 centres. The long survival period in animals with divided cord 

 may also be due to the marked fall of temperature, caused by the 

 prolonged artificial respiration by which the animals are reduced 

 to the poikilothermic or hibernating condition, in which they 

 are able to survive for a long time with minimal renewal of 

 pulmonary air. 



Langendorff endeavoured to sustain his theory of there being- 

 only an inhibitory and regulatory centre for respiratory move- 

 ments in the bulb their activity being due solely to the spinal 

 centres by showing that mechanical, electrical, and chemical 

 stimulation of the floor of the fourth ventricle, in chloralised 

 rabbits, induced phenomena of respiratory arrest, which ceased 

 with the excitation. 



On the other hand Kronecker and Marckwald (1887-89), on 

 repeating the experiments with rabbits in which the spinal bulb 

 was separated from the cerebrum, obtained quite opposite results. 

 Eespiration was accelerated by electrical stimulation of the bulb, 

 which also caused respiratory movements, intercalated between 

 those made by the animal. This was confirmed by Aducco (1889) 

 on intact and non-anaesthetised dogs, both with electrical excita- 

 tion of the sinus rhomboidalis (Fig. 204), and with its chemical 

 excitation by a crystal of sodium chloride. 



The effects of applying cocaine to the bulb, as determined by 

 Aducco's experiments, are even more striking. When, e.g., cocaine 

 hydrochloride (either in the form of crystals, or as a powder mixed 



