Manual of nature study. i61 
(< b ) The lymph, its composition and use, 
circulation of lymph. Arrangement 
and structure of lymphatic vessels. 
(c) The circulation of the blood, how carried 
on, the heart as a force pump. Action 
of the valves of the heart. 
(d) Structure and function of the heart 
arteries, veins and capillaries. Rela¬ 
tion to each other, capillary attraction, 
etc. Changes the blood undergoes 
during circulation. 
(e) Hygiene of the circulatory system. 
Effects of alcohol and narcotics. 
Respiratory System. 
(a) Composition of air, diffusion of gases, 
evaporation, heat, animal heat, radia¬ 
tion, etc. 
(i b ) The skin as a respiratory organ. Struc¬ 
ture and function. 
(c) Inhalation and exhalation, how carried 
on. Organs of. Structure and func¬ 
tion of respiratory organs. Adapta¬ 
tion of structure to function. 
(d) Relation of respiration to circulation 
and digestion. 
(e) Hygiene of the circulatory organs. Ven¬ 
tilation and heating, exposure, dress, 
etc. 
