OF DISEASE GERMS. 



323 



although exposed time after time to the influence of 

 contagious disease, reach old age without having- suf- 

 ferred from a single attack, ought surely to encourage 

 and afford a justification to those who, having deter- 

 mined to devote themselves to the service of the sick, 

 must be continually exposed to contagion. At the 

 same time these facts point to another very important 

 conclusion, namely, that we may keep our bodies in 

 such a state as will enable them to bear free exposure 

 with little danger of invasion. But, unfortunately, 

 the knowledge we have at present is not sufficient to 

 enable us to indicate precisely either the state of the 

 system or of the blood, which would certainly enable 

 us to resist the influences of the contagious particles, 

 or the state in which it would be extremely dangerous 

 to expose ourselves to the poison. Without doubt, 

 persons whose health is impaired, those who are 

 actually suffering from, or who have recently become 

 exhausted by prolonged watching, mental anxiety, or 

 oveV fatigue, should avoid the sick. who are suffering 

 from any form of contagious fever. A state of health 

 which for some time has been characterized by loss of 

 appetite, with nervous listlessness, wakefulness at 

 night, and muscular weakness, seems particularly to 

 favour invasion by contagious poisons. On the other 

 hand, those who seem frequently to be ailing, and 

 who suffer from that condition known as biliousness, 

 certainly often, though it cannot be said invariably, 

 escape although freely exposed. 



