ELEMENTARY EXPERIMENTAL PHYSIOLOGY 75 



violent muscular exercise, and repeat the observations at 5-minute 

 intervals till it is again normal. 



(Read Temperature Regulation in Text Book.) 





III. THE ESSENTIAL NATURE OF LIVING MATTER IN 

 ITS SIMPLEST FORM 



1. OBJECT. To learn something of the essential nature of living 

 matter (protoplasm). 



2. METHOD. Take a very simple form of living matter the 

 yeast plant and place it under various conditions. Place a small 

 quantity of yeast on a slide, and add a drop or two of water. Rub 

 up into an emulsion with a glass rod, and transfer a little on the 

 end of the rod to : (A) a test-tube of a solution containing the 

 chemical elements which occur in the yeast, C.H.O.N.S. and P., e.g. 

 urea QO(NH 2 ) 2 , glucose C 6 H 12 O 6 , with traces of sodium phosphate 

 Na 2 HP0 4 , potassium sulphate K 2 SO 4 , and calcium phosphate 

 Ca 3 (PO 4 ) 2 ; (B) a test-tube filled with water. 



See that the tubes are quite full. Shake well and examine a 

 drop with the microscope, and make a rough estimate of the number 

 of torulae in two or three fields of the microscope. Draw one or 

 two torulse. 



At each Bench 



Students at places 1 and 2 at once insert the corks firmly into 

 the tubes. The tubes of 1 are placed in an incubator at 37 C. 

 The tubes of 2 are placed in a vessel of broken ice. 



Students at place 3 introduce a few drops of phenol solution, 

 insert the cork, and place the tubes in the incubator. 



Students at place 4 boil the tubes before quite filling them, cool 

 them under the tap, fill them with water, insert the corks, and 

 place them in the incubator. 



3. RESULTS. (A) ON YEAST. Next day the tubes are to be 

 examined with the naked eye before and after shaking, and the 

 condition of each tube studied, contrasting it with the condition 

 on the previous day. A drop of the fluid after shaking is to be 

 examined with the microscope, and the number of torulae in two or 

 three fields to be estimated. 



The students at each bench should make a combined table of 

 their results as to gas-formation, change in opacity, and change in 

 number of torulse, using -f and as signs. 



