190 TRANSACTIONS LIVEEPOOL BIOLOGICAL SOCIETY. 



Water is made up of oxygen and another gas 

 called hydrogen. But water also contains air dissolved 

 in it. When water is boiled, it loses its air, and until it 

 dissolves more air marine animals, like fishes, can not 

 live in it. 



Experiments will be made in order to prove these 

 statements. 

 The Breathing of Animals. 



Most large animals that live on the land breathe by 

 means of lungs. Oxygen is taken into the substance of 

 the body, and carbonic acid gas is given out. Plants also 

 breathe in oxygen and give out carbonic acid gas. 

 Marine animals obtain their oxygen from the sea water by 

 means of gills instead of lungs. 



Second Day. 



The Structure of a Fish. 



The stomach, the liver and the digestion of the food. 



The blood, heart and gills ; the circulation of the 

 blood through the body. 



The red blood of a fish consists of a clear colourless 

 liquid, in which there are a great number of small reddish, 

 oval particles, about ^o part of an inch in diameter. 

 These are the corpuscles, and their use is to carry the 

 oxygen to the tissues of the animal. 



The heart is a force-pump, which propels the blood 

 all through the body. From the heart the blood goes to 

 the gills, where it takes in oxygen from the water, and 

 gets rid of its carbonic acid gas. It then flows in the 

 blood vessels all through the body. 



The brain, the nerves and the senses. 



The Breeding of a Fish. — Fishes are either male 

 or female, but with the exception of the skates, rays, 



