MODE OF SPREAD OP INFECTIVE DISEASES. 771 



more especially linen, beds, &c. ; it is further necessary 

 to keep all these sources of infection in a moist state 

 till they can he disinfected, so that the infective 

 agents may not become detached and carried away by 

 currents of air. (This is unnecessary in cholera.) All 

 surrounding objects which might retain the infective 

 agents, and which are difficult to cleanse, should be re- 

 moved as far as possible, and protected from con- 

 tamination (for example, soil, &c., the doors and walls 

 of sick-rooms should be closely covered with some im- 

 permeable material). Those who come in contact with 

 the sick should be particularly cleanly, and should also 

 wash with sublimate or carbolic lotions ; similar cleanli- 

 ness is also necessary with regard to the clothing, the 

 dwelling, the kitchen, &c. It is also desirable that those 

 who are particularly predisposed to one or other disease 

 on account of the presence of abnormal points of invasion 

 (as in the case of wounds, catarrhs, gastric disturb- 

 ances, &c.) should avoid the danger of infection, and 

 should observe the necessary precautions even when no 

 evident sources of infection are present. 



b. Special precautions in individual diseases. In special pre- 

 the case of the acute exanthemata we must attempt by ^diridaar 

 rubbing oil over the skin of the patient to prevent, or at diseases, 

 any rate to limit, the detachment of the infective agents 

 from the surface of the body, and their transport through 

 the air. Thorough ventilation of the sick-room, which 

 is much recommended for prophylactic purposes, can, it 

 is true, lead to a dilution of the germs, but it is difficult 

 even by the best methods of ventilation to diminish the 

 chances of infection to such an extent as occurs in the 

 open air, and as is requisite if we are to place ventila- 

 tion on the same footing as the other prophylactic 

 measures. 



In those diseases in which the seat of invasion and 

 the seat of the disease lie in the intestinal tract, such as 

 cholera and typhoid fever, we must, when there is a great 

 danger of infection, pay the greatest attention to the 

 preparation of the food, and we must also see that the 

 drinking water comes from pipes or from good wells, 



