109 
SYLLABUS OF THE LESSONS GIVEN IN THE 
CLASSES FOR FISHERMEN. 
Two lessons are given each day, each lesson lasting for 
about two hours. 
First Day. 
The work of the first lesson is introductory, and will 
deal with the use of the microscope and dissecting tools. 
Before going on to the study of fishes and other 
marine animals, it is necessary to learn something about 
water and ai, so as to understand the way in which 
animals breathe. 
The Atmosphere.— Air consists chiefly of three gases, 
nitrogen, oxygen and carbone acid gas. In every 10,000 
parts, by bulk, of air there are a little less than 2,100 
parts of oxygen, about 7,900 parts of nitrogen, and about 
four parts of carbonic acid gas. 
The oxygen of the air is necessary for the breathing 
of animals and plants, and for combustion. Without it 
animals or plants would not live, and fuel would not burn. 
When an animal breathes, oxygen is taken into the body, 
and combines with certain substances in the muscles and 
elsewhere, producing mechanical energy and heat. When 
a piece of charcoal or coke burns in the air, it combines 
with oxygen. 
Nitrogen is not really necessary for breathing or for 
combustion. It merely serves to dilute or weaken the 
oxygen. 
Carbonic acid gas in the air comes principally from 
the breathing of animals and from combustion of fuels. 
