PREFACE vi 



XVII. Endocrine control and hormones 



1. General nature of hormonal action 



2. Hormonal control of the sexual cycle 

 in animals 



3. Hormonal control of plant growth 

 and development 



XVIII. Physiological mechanisms: structure and 

 function 



1. The nervous system 



a. Nerve: structure, membrane po- 

 tentials, the nerve impulse, spon- 

 taneous activity 



b. Receptors: generator potentials 



c. Nervous integration: synapses, re- 

 flex arcs, organization of the spinal 

 cord, autonomic nervous system, 

 brain 



2. Muscle 



a. Muscle structure and function 



b. The chemistry of muscular activity 



3. Digestion 



a. The course of digestion; enzymes 



b. Absorption, transport of food 



c. Role of the liver 



4. Osmotic and ionic balance 



a. Kidney structure and function 



b. Ionic composition of blood and 

 tissues 



c. Regulation of pH 



5. The blood 



a. Blood cells and plasma 



b. Immunological reactions 



c. Individuality: problems of transfu- 

 sion and organ transplantation 



d. Respiratory pigments : transport of 

 oxygen and carbon dioxide 



XIX. Evolution and its mechanisms 



1. Time scale of evolution; major events 

 in animal and plant evolution 



2. Mechanisms of evolution: natural 

 selection, artificial selection, sexual 

 selection 



3. Biochemical evolution 



(For traditional discussion of mech- 



anisms of evolution and phylogeny we 

 rely principally upon the reading.) 

 4. The evolution of man 



It may be helpful also to say something of our 

 laboratory facilities. Our introductory labora- 

 tories formerly had been furnished only with very 

 low tables, bearing only microscope lamps, sup- 

 posed to facilitate long hours of microscopy, and 

 incidentally to keep the students fixed in posi- 

 tion. This kind of thing has been more or less 

 standard laboratory furniture for biology courses 

 in the past. 



In the present course we have stand-up 

 benches, with adjustable stools for when the 

 student must sit. The benches are in double rows, 

 back to back, with facilities and a drain running 

 down the middle. The facilities at each place in- 

 clude water outlets (one equipped with an 

 aspirator), electricity, and gas. At the end of 

 each double pair of benches is a large sink, for 

 washing up and other uses. 



The stand-up benches are important. They do 

 not prevent microscopy, which seems to go as 

 well on high stools and benches as nearer the 

 floor. On the other hand, our students are not 

 fastened down. They move about a great deal 

 during a laboratory session, talking with one an- 

 other, seeing what other students are doing, 

 frequently going to the blackboard to argue a 

 point. This is of course just what we want. If 

 one of our laboratory sessions seems inordinately 

 quiet and orderly, we know that something is 

 wrong and try to stir it up. 



To assist instructors in setting up, we have ap- 

 pended lists of materials and apparatus at the 

 end of each exercise. We reserve one afternoon 

 per week, on which no laboratory sessions are 

 held, for setting up and going over the week's 

 work with the graduate assistants. It will prob- 

 ably not surprise the readers of this manual to 

 learn that a number of the exercises involve 

 procedures that were new to most of our grad- 

 uate students, and indeed to most of the staff 

 including the professor in charge. This is a 

 symptom of what it means to be teaching the new 

 biology. 



