316 INFECTIONS OF THE DIGESTIVE TRACT 



be indicated by a line running at a considerable rather 

 than a slight distance above the critical line. The 

 mere crossing of this line in an upward direction 

 connotes the disappearance of symptoms. But this 

 does not necessarily mean health, because there may be 

 a margin so small that it is quickly exhausted by a detri- 

 mental influence. On the other hand, very pronounced 

 symptoms may exist (especially hi cases of short dura- 

 tion) without these symptoms necessarily possessing a 

 grave significance. A slight improvement in physiologi- 

 cal conditions is sufficient to make the line indicative of 

 derangement in function cross the critical line of demar- 

 cation between physiological and pathological conditions. 

 This conception of the part played by symptoms as an indi- 

 cation of actual states of functional activity is helpful in 

 explaining why some cases are so much more refractory 

 than others. In long standing conditions, in which a high 

 grade of intestinal putrefaction has for some time been 

 present, improvement is extremely slow even under the 

 most favorable hygienic conditions. There is a dis- 

 couraging persistence of symptoms until the critical line 

 is reached. The depression of function is, however, so 

 considerable that there may be a real gain in function 

 without an immediate and corresponding subjective im- 

 provement. In such cases the patient seldom accumu- 

 lates an adequate functional reserve even after the 

 disappearance of all obtrusive symptoms. The line 

 representing his physiological condition must be traced 

 close above the critical line, and a slight depression in 

 function is promptly 'followed by a return of symptoms. 



