202 INFECTIOUS AND PARASITIC DISEASES. 



(c) Entry: Not known, probably through bite of 



insect, e.g., bed-bug. 



(d) Exit: Probably through bite of suctorial insect. 



(e) Contracted : Seems to be contagious ; but as only 



seen where over-crowding, and where 

 hygienic conditions are bad, probably 

 conveyed by insect. 



(f) Disinfection : Nothing known of the micro-organ- 



ism outside of the body. 



(g) Prophylaxis: Plenty of fresh air, good food, 



and personal cleanliness, are probably the 

 best means of avoiding the infection. 

 Screen houses against mosquitoes, flies, 

 etc., and wage war against all vermin such 

 as bed-bugs, roaches, etc. 



Rubella (Rotheln, German measles). 



(a) Cause: Not known. 



(b) Localization: Blood, skin, respiratory tract. 



(c) Entry: Probably through respiratory tract. 



(d) Exit : Respiratory tract and probably emanations 



from skin. 



(e) Contracted: Resembles measles (which see). 



Scarlet Fever. 



(a) Cause: Not known. 



(b) Localized : Throat ; blood ; skin ; in complicating 



suppurations, e.g., ear. 



(c) Entry: Respiratory tract; also wounds. 



