36 EXPERIMENTAL GENERAL PHYSIOLOGY 



The incline of the ciliated surface may be changed by resting it, 

 at different angles, against the block of wood as shown in Fig. 12. 



4. Observations. (1) If the preparation is successful, the piece of 

 metal will be slowly carried up the incline. Should it fail, a thinner 

 piece of lead or a new preparation may succeed. With a given 

 incline, is the small piece of lead carried more rapidly than the 

 large piece? 



(2) If W = work done, g= weight in milligrams and h= height in 

 millimetres, then W=g X h would give the work in milligram- 

 millimetres. 



(3) Determine the distance through which the weight is carried 

 in a unit of time (one minute is a convenient unit of time to use), 

 when the incline is placed as shown in Fig. 12. 



(4) With the apparatus so adjusted, what is the value of h when 

 the distance which the weight moves is 1 cm. ? Does the thickness 

 of the cork board need to be considered? 



(5) What is the work per minute, expressed in milligram- 

 millimetres? 



(6) What is the work per minute, expressed in gram-centimetres? 



(7) What is the work per minute, expressed in ergs? (An erg= 

 1 dyne X 1 cm.; 1 dyne= 1 gm. divided by 981 or 1 gm. = 981 dynes; 

 therefore, 1 gram-centimetre 981 dyne-centimetres. To express 

 work in ergs find the gram-centimetres and multiply by 981.) 



(8) What is the "activity" of the cilia in work per second f 

 Divide ergs per minute by 60 to get ergs per second. 



(9) Using the same incline of the cork board, with which weight 

 do you get the greatest activity? 



(10) Using the weight which gives the greatest activity, find the 

 degree of incline which yields the greatest activity of cilia. 



(11) What significance has the variation of the thickness of the 

 lead weight? Determine the upper limit of thickness. 



(12) Would it be possible to determine the amount of work accom- 

 plished by each cilium? By each stroke of a cilium? 



