PRACTICAL STUDY. 45 



6. Add to some oil in a test-tube either turpentine, chloro- 

 form, or ether. Report your results. 



E. Dialysis. 



1. Place in a freshly prepared dialyser a strong (50) solu- 

 tion of glucose, and put the dialyser in a vessel of distilled 

 water. Set the vessel aside for half an hour. Note the rise of 

 liquid in the dialyser. Then test the water outside the dialyser 

 for glucose by Trornmer's test. What do you conclude ? 



2. Place in a fresh dialyser some diluted white-of-egg. Place 

 the dialyser in distilled water as before, and after a number of 

 hours (5-2-i) test the water for proteids by one of the tests given 

 above. What do you infer ( 



3. Test another portion of the water with silver nitrate solu- 

 tion, and another with barium chloride. What do you infer? 



F. Temperature. 



1. Observe the beating heart of a frog whose brain has been 

 destroyed by the demonstrator. Count the beats at the ordinary 

 temperature ; again, after the organ is bathed with iced normal 

 fluid; then when treated with normal fluid heated to 38 C.; 

 and finally when- treated with normal fluid at 65. Record your 

 results. 



2. If possible, repeat this experiment with the heart of an em- 

 bryo three-day chick, in which similar effects may be beautifully 

 shown. 



3. Mount cells of Nitella, Anacharis, or Vallisneria, showing 

 rotating protoplasm, and support the ends of the slide by bits of 

 thick pasteboard so that they do not come in contact with the 

 stage of the microscope. Having noted the rate of flow, place a 

 large heated coin on the slide near the object. If necessary, re- 

 heat and replace the coin until an effect is observed. Note the 

 results. 



i. Now replace the coin by one which has been in iced water, 

 renewing if necessary. Note the results. 



5. Heat some active Nitella thoroughly to 50 C. Examine 

 with the microscope,, aTid note the results.* 



' These experiments can be more accurately performed by using a warm 

 stage. 



