154 STUDIES IN PHYSIOLOGY 



corrosive sublimate, carbolic acid, or some other germ-de- 

 stroying solution. Antiseptic tablets can be obtained at any 

 drug store, and a solution can be made by dissolving a tablet 

 in a pint of water. This should be kept on hand and used 

 to wash out wounds. The injury should then be covered 

 with cotton soaked in the poison solution and bandaged, to 

 prevent the entrance of other germs. If this is not done, 

 bacteria are likely to settle in the wound, and healing may 

 be delayed or even more serious results may follow. With 

 proper treatment a wound should show no signs of the 

 formation of pus, should not cause pain, and should heal 

 rapidly. 



Effect of Alcohol on the Organs of Circulation. Alcohol " ex- 

 cites the vascular system, accelerates the circulation, so that 

 the muscles and nerves are more active, owing to the greater 

 supply of blood. It also gives rise to a subjective feeling of 

 warmth. In large doses, however, it paralyzes the vessels, 

 so that they dilate, and thus much heat is given off and the 

 temperature is lowered. 1 The action of the heart also be- 

 comes affected, the pulse becomes smaller, feebler, and more 

 rapid." " Text-book of Human Physiology," LANDOIS and 

 STERLING. 



6. A COMPARATIVE STUDY OF THE CIRCULATION 



Circulation in the Earthworm. If we examine the upper 

 or dorsal surface of a living earthworm, we see through the 

 skin a tube through which the blood is driven in pulses. 

 This is called the dorsal blood vessel. Near the anterior end 

 of the body, five pairs of large blood vessels (a-or'tic arches) 

 branch off from the dorsal blood vessel just mentioned, sur- 

 round the esophagus, and connect with a large blood tube 

 that lies beneath the alimentary canal. The aortic arches 

 pulsate like the dorsal blood vessel, and thus help to force 

 the blood through the body. Branches of the dorsal and 



i For discussion of effect of alcohol on body temperature, see p. 243. 



