GENERAL ANIMAL FUNCTIONS. 97 



going forward; and (3) guiding the body in a given 

 direction. Which of these gives the most trouble to the 

 animal in each of the following conditions: moving 

 through air, through water, on the surface of the ground, 

 or in burrowing? Study some of the organs by which each 

 of these things is accomplished in each of these conditions. 



7. How much do animals differ in their rate of loco- 

 motion? On what do the differences depend? 



8. What senses has a dog or a cat? How do you 

 prove your conclusions? 



9. Can you compare a color sensation with one of touch? 

 Why? Can you compare an odour and a sound? Can 

 you compare a taste and an odour? Can you compare a 

 sensation of sweet and of bitter? Can you compare a 

 high tone with a low one? warm with hot? different 

 grades of sourness? What is the point in these questions? 



10. The three functions of our eyes are : (i) light sen- 

 sation, (2) color sensations, and (3) formation of images 

 of objects. Do all the simpler eyes of lower organisms 

 give all three of these classes of information? Which 

 probably appears first? Evidences. 



11. Discover, by reference to books of Physics, the 

 simpler facts as to the absorption or osmosis of dissolved 

 substances. At what points in the nutritive process of 

 higher animals must this absorption take place? 



102. Technical Terms to be Defined. Metabolism; growth; sexual 

 reproduction; non-sexual reproduction; cilia; organ; ingestion; 

 digestion; assimilation; respiration; oxidation; excretion; absorp- 

 tion; osmosis; gland; gill; lung; trachea; lymph; heart; capillary; 

 blood corpuscles; kidney; skeleton; cuticula; mass; ovary; ovum; 

 sperm; sensory end organ; ganglion cell; afferent nerve; efferent 

 nerve; otocyst. 



