8 



Proofs that all parts of living beings possess the power of select- 

 ing the materials of their growth from the sap or the blood, 

 or complete the construction of their own particles This 

 process simple in simple animals, but more complex in others 

 The fluids constantly changed in character, until converted 

 into solidsr ASSIMILATION. 



LECTURE lit 



Integrity of the Surface in ftnimals The Vital Functions all 

 carried on under cover Stages of Assimilation Motive 

 Powers, fyc. 



Explanation of the meaning of SURFACE, as applied in physiolo- 

 gy The surface of an animal or plant may be extended by 

 art Illustrations Slit ears of Indians Slit lips in Van 

 Dieman's Land Boring the ears, &c. Surgical cases. 

 Both the inner and outer surfaces of living bodies being covered 

 by a shield or envelope of cuticle or mucous membrane with- 

 out any openings, how does food enter? All membranes 

 have the power of transmitting certain fluids A bladder 

 transmits alcohol much faster than water Living mem- 

 branes have a vital power of choosing or rejecting. 

 Explanation of ABSORPTION. 



Some animals absorb by their whole surface Nature and use of 

 stomachs DIGESTION, the first step in the process of assimi- 

 lation Vegetable stomachs Dionaea muscipula Sarace- 

 nia flava Pitcher plant Parasitic plants. 

 Absorbed fluids are organised from the moment they enter the 



body they supply every part with nourishment. 

 Hence the necessity of a CIRCULATION. 

 Reciprocal action of solids and fluids DEPOSITION. 

 Result of deposition NUTRITION. 



Substances separated from the blood or sap by SECRETION 

 Examples of the secretions Saliva, tears, the water in the 

 leaves of saracenia, perspiration, &c. Nutrition is a form 

 of secretion. Perspiration, cuticle, shells, mucus, &c. are 

 secretions. 



