76 GENERAL PROPERTIES OF LIVING TISSUES 



the nerve or the negative charge leaves the 

 nerve. 



The break induction current is more effective 

 than the make, as the slower development of the 

 latter causes the terminals of the secondary wire 

 to be charged more slowly than by the rapidly 

 developed break current. 



APPARATUS. 



Normal saline. Bowl. Towel. Pipette. Glass plate. 

 Zinc wire, 4 inches long. Copper wire, 4 inches long. Por- 

 celain dish. Mercury. 5 per cent sulphuric acid. 5 per 

 cent solution of potassium chromate. Iron wire, 4 inches 

 long. Muscle clamp. Iron stand. Capillary electrometer. 

 Rheochord. Microscope (micrometer ocular, objective 3). 

 Daniell cell. Dry cell. Two platinum electrodes. Zinc 

 electrode. Beaker. Sodium chloride. Simple key. 9 

 wires, 2 feet long. Saturated solution of copper sulphate. 

 Pole-changer (in paper dish). Inductorium (with elec- 

 trodes). Coil with few windings (primary coil of a 

 second inductorium). Bar magnet. Iron filings. Galva- 

 nometer. Card, with thick copper wire. Ligatures. 

 Frogs. Osmometer (for demonstration). Tradescantia 

 discolor. Serum. Sodium chloride solutions (0.60, 0.65, 

 0.70, 0.75, 0.80 and 5.0 per cent, also 0.62, 0.61, 0.60, 

 0.59, 0.58, and 0.57 per cent). Microscope. Defibrinated 

 blood. Twelve test-tubes. Tension indicator. Soap solu- 

 tion. Lycopodium. Alcohol. 



