Theories and Experiments 477 



(page 414) , that the organs contained in the cranial cavity escape 

 more or less completely the effect of the compression exerted on 

 the rest of the body: 



If more activity and clearness of mind are observed under 

 increased atmospheric pressure, this phenomenon may be attributed 

 to another cause than the rise of the barometer of an inch or an 

 inch and a half, and we cannot draw any conclusion from it in favor 

 of the increase of pressure. When Junod maintains that under a 

 certain pressure the sphere of ideas enlarges, and that one becomes 

 capable of writing verses, his claim seems extravagant to me. More- 

 over, my observations conflict with those of Dr. J. Lange. He says 

 that under the influence of compressed air the central nervous system 

 is stimulated in a peculiar way, that in particular the functions vested 

 in the cerebral hemispheres are carried on with greater activity, that 

 in many persons one observes more or less definitely an elasticity 

 and brilliancy of mind which did not exist before. The patient sub- 

 jected to the treatment is supposed to experience a mental well 

 being, and his mind is clearer and freer. In addition, he thinks that 

 he can consider these phenomena as constant effects of compressed 

 air. 



In my numerous observations, I have noted nothing of the sort. 

 On the contrary, I have observed in myself and others a feeling of 

 calmness, generally followed by a tendency to sleepiness. 



Compressed air cannot act directly upon the organs contained in 

 the cranial case, whereas all the other parts of the body undergo its 

 effects: so one might assume that even a slight increase of the atmos- 

 pheric pressure brings more blood to the brain. The tendency to 

 sleepiness would also suggest such a conclusion. Dr. Vivenot con- 

 ceived the idea of observing this increase of pressure by means of 

 the dilatation of the pupil. 



He placed in a spectacle frame a thread divided into milimeters, 

 and measured by means of a concave mirror the size of the pupil 

 before and during the treatment, using candles in both cases, in order 

 to have equal lighting. Strangely enough, he most frequently observed 

 a contraction of the orifice of the pupil, which must be attributed 

 to a stimulation which, as I have already said, was not indicated in 

 myself by any other sign. (P. 29.) 



Let us quote also an interesting discussion of the changes in the 

 lymphatic circulation: 



An increase of appetite is usually observed in persons who have 

 taken treatments of compressed air for some time. Some of them lose 

 a little weight at the beginning, but soon their appearance improves 

 and they gain weight. Dr. J. Lange gives the following explanation 

 of this fact: The blood contained in the subclavian vein undergoes 

 suction and therefore the lymph which comes from the thoracic canal 

 would flow there more abundantly, and besides, the thoracic canal 

 itself, which is hermetically inclosed in the chest, would also be sub- 

 jected to negative pressure, and consequently the lymph contained in 



