388 APPLIED PHYSIOLOGY 



Thirdly. A variety of chemical substances called anti- 

 septics are poisonous to bacteria and destroy them almost 

 at once. Carbolic acid added to from twenty to one hun- 

 dred times its weight of water is very efficient in destroy- 

 ing germs which it can touch. Bichloride of mercury 

 added to from one thousand to five thousand times as 

 much water, is also very good, but it destroys iron or tin 

 vessels. Chloride of lime is also much used. 



Substances must come into intimate contact with germs in order to 

 kill them. A little carbolic acid or other antiseptic may impart an 

 odor to a room or overcome a smell, but to destroy the germs it must 

 be applied in quantity directly to the germ. 



Before a surgical operation the surgeon washes and sterilizes his 

 hands, and covers his clothes with a sterilized gown. He carefully 

 avoids touching any object which has not been sterilized either by heat 

 or by chemicals. Before he operates he scrubs and sterilizes the field 

 of operation just as he did his hands, and then surrounds it with steril- 

 ized towels. At the end of the operation he covers the wound with a 

 dressing which has been sterilized by heat or chemicals. Then no 

 germs can enter, and the largest wounds heal in a few days without 

 pain or discharge. The safety of operations now as compared with 

 those of forty years ago lies in the discovery of how to exclude germs 

 of disease. 



691. Care of a sick room. When a person is sick, every 

 effort should be made to exclude germs of sickness. Fresh air and 

 sunshine are always of the utmost importance in a sick room. It will 

 always be better to run the risk of having the room a little cold than to 

 have its air close. 



In contagious and infectious diseases, air and sunlight are the chief 

 means of destroying the germs. 



Cleanliness should always be enforced in a sick room. The night 

 clothes and bed linen should be changed as often as they are soiled. 

 The whole body should be bathed daily, and the teeth and mouth 

 cleansed. 



Talking above all things disturbs a patient. Especially avoid all 

 references to doleful cases of suffering like the patient's. Do not ask 



