422 Mr. W. F. R. Weldon. Note on the [Nov. 27, 



sound produced at the junction of the trachea with the air bag. The 

 origin of the sound at the bifurcation has been discussed above. That 

 a sound is produced in the breathing lung is proved by the experiment ; 

 it seems probable that its cause is the passage of the air from the 

 small bronchi into the vesicles. 



In the living body, when there is stasis of air in a bronchus, the 

 new sound formed at the mouth of the bronchus must be added to the 

 pre-existing glottic and pulmonary sounds, and is no doubt one factor 

 in the production of puerile or exaggerated breathing ; the increased 

 rapidity of motion of the air in the healthy lung being another. 



With regard to the production of the vesicular or as it may now be 

 called the pulmonary sound ; if a lung be partially inflated and the 

 bronchus tied it may be made to expand and contract freely by 

 placing it in an air-tight vessel completely filled with water, and 

 communicating by means of a flexible tube with a vessel containing 

 mercury. Raising or lowering the mercury causes the lung to contract 

 and expand. Under these circumstances there is no current of air 

 through the bronchi ; as the vesicles are more extensible than the 

 bronchial tubes, a slight current must enter them during expansion, 

 but this appears to be insufficient to produce a sound, as none could 

 be heard with certainty through a stethoscope applied directly to 

 the lung. The experiment shows that the pulmonary sound is not due 

 to the movements of the tissues of the lung. 



The results of the experiments now described are in accordance 

 with the third theory quoted at the beginning of this paper, and the 

 results of the vivisections performed on horses by Chauveau, Bondet, 

 and Bergeon are confirmed by my experiments, which show that the 

 vesicular sound is produced in the lungs, and not in the glottis or 

 trachea. 



The demonstration of the production of a new sound in bronchial 

 obstruction I have not seen elsewhere. 



III. " Note on the Origin of the Suprarenal Bodies of Verte- 

 brates." By W. F. R. WELDON, B.A. Communicated by 

 Professor M. FOSTER, Sec. R.S. Received October 30, 1884. 



In the early part of this year I was enabled, by the courtesy of the 

 Royal Society, to examine some specimens of Bdellostoma Forsteri, 

 collected by Mr. Sedgwick by means of a grant from the Society. As a 

 result of this examination, it appeared that the head kidney, described 

 by Johannes Miiller as connected, on the one hand with the segmental 

 duct, and on the other by means of a branch of segmental tubules with 

 the pericardium, had become modified in a very peculiar manner. The 



