484 



Dr. A. B. Garrod. On the Place of [June 10, 



The state of the muscle after section of its nerves is that of 

 " tonus." 



Atropine by acting directly on the unstriped muscular tissue, and 

 paralysing it, can produce a greater dilatation than mere section of 

 the third nerve, and so also on section of the third nerve eserine 

 directly stimulating the muscular fibre gives rise to extreme 

 contraction. 



The intra-ocular muscles therefore have a similar anatomical, histo- 

 logical, and physiological action, and they also are associated together 

 during the act of accommodation. The pupil contracts on accommo- 

 dating, and dilates on relaxation of the ciliary muscle ; the former 

 action is by means of the third as motor nerve of the pupillary and 

 ciliary muscles, and the latter is through the long ciliary nerves from 

 the nasal branch of the fifth. 



The ordinary light reflex of the pupil takes place by the third, as 

 the motor nerve, and the cervical sympathetic as the inhibitory nerve 

 giving rise to dilatation of the pupil. The two chief actions of the 

 pupillary muscle are thus divided off from one another in mammals. 

 In birds possessing voluntary control over their irides this is not so, 

 and the cervical sympathetic has no power over the pupil, the nerve 

 producing dilatation of the pupil being the trigeminus. 



V. " On the Place of Origin of Uric Acid in the Animal Body." 

 By Alfred Baring Garrod, M.D., F.K.S. Received 

 June 8, 1886. 



(Abstract.) 



The endeavour of the author in this communication has been to 

 show the place of origin of uric acid in the animal body, and to 

 ascertain which of the two hypotheses on the subject is correct, viz., 

 whether uric acid is first present in the blood and then secreted from 

 the blood by the kidneys, or whether it is formed by the kidneys 

 themselves. To enable him to satisfactorily prosecute many of his 

 observations, the author has devised a new method for discovering the 

 presence of uric acid in very minute quantities of blood. 



The results of his investigations are embodied in the form of the 

 nine following propositions : — 



Prop. I. — Uric acid is secreted by the kidneys as ammonium urate, 

 and in the case of birds and reptiles, whose urine is 

 semi-solid, it is found in a definite physical form, more 

 in the vitreous condition than in the truly crystalline 

 shape. 



Prop. II. — Uric acid, when present in the blood, is found under the 



