802 SEC. 18. BIOLOGY. 



3. Hollow and lancet. 



4. Three canals of steel, reed-shaped, to fix in the regulating 



canal. 



5. Two pincers for compression. 



6. Tube of gum elastic for joining the regulating canals to the 



arterial canal. 



More detailed explanations as to the mode of setting up the 

 apparatus, and the different positions of the internal tube as to 

 the regulating canal, will be found in the description of the 

 apparatus, two copies of which, with sketches and plans, are 

 appended. 



Dr. Giuseppe Albini, Professor of Physiology in the Royal 

 University of Naples. 



VII. ELECTRICAL APPARATUS USED IN PHYSIO- 

 LOGY. 



3789. Hermann's Universal Commutator, with adjustable 

 contact-springs. Professor Dr. L. Hermann, Zurich. 



This apparatus may be turned by hand or by water power, and admits of 

 many physical and physiological applications, e.g. : 1. Closing a simple 

 electrical circuit ("interrupter"). 2. Change of direction in a simple 

 electrical current ("in versor"). 3. The same in two circuits, for instance, 

 in determining resistance in a polarizable conductor, by Wheatstone's 

 method, under currents of changing direction. 4. Choice between opening 

 or closing induction currents (Dove's "Disjunctor "). 5. Determination of 

 the polarization residuum in a conductor after shutting the current (like 

 Siemens's " Commutator "). 6. Comparison of two residua of polarization, 

 by connecting the two conductors with the galvanometer, one opposite to 

 the other. 7. Many physiological rheotomic inquiries. 



3790. Hermann's Non-Folarizable Electrodes, of large 

 form. Professor Dr. L. Hermann, Zurich. 



By this apparatus a nerve may be connected with any number of non- 

 polarizable electrodes in a small space, for instance, in the wet chamber of a 

 myograph. The ends of the zinc wires, well amalgamated, receive a covering 

 of clay, mixed with saturated solution of sulphate of zinc, and above this a 

 small quantity of clay mixed with 0' 6 per cent, solution of chloride of sodium. 



379Oa. Becquerel's Thermo-Electric Apparatus for 

 Physiological Purposes. M. Ruhmkorff. 



3791. Electric Excitors. T. Haivksley. 



3792. Daniell's Constant Current Batteries for Clinical 

 use. . T. Haivksley. 



3793. Dr. Herbert Tibbit's Current Battery and Induc- 

 tion Apparatus. T. Hawhsley. 



