XXV111 INTRODUCTION. 



for examining the throat, enables us to appreciate changes in the organ of speech, 

 which, without its aid, could not have been suspected, and to determine with 

 certainty the presence of other diseases, which, without it, could only have been 

 suspected. The ophthalmoscope, or instrument for examining the eyes, has afforded 

 valuable information in the detection of disease not only of the organ to which it 

 is more especially directed, but also of the brain. The weighing machine is of 

 great importance in determining the progress, that is, the advance or otherwise of 

 wasting diseases, and of the value of the treatment being pursued. At our hospitals 

 it is customary to weigh the patient at certain stated intervals, say once a fortnight, 

 and to record their weight on cards provided for that purpose. "We need hardly 

 point out the necessity in making observations on the weight, of always using the 

 same instruments, and more especially of the patient always being weighed in the 

 same clothes. 



"Wasting or emaciation is sometimes the first observable symptom of disease. 

 It is early seen in the countenance, partly because it is uncovered, partly because 

 a slight diminution of the fat under the skin of the face produces a striking 

 alteration in the features. It occurs in complaints that are not commonly 

 dangerous, as in indigestion, and in hypochondriasis, which is often connected with 

 indigestion. When it does appear it marks the reality of the disease. This 

 wu sting happens also in many serious maladies, for example, in consumption and 

 dropsy, although the dropsical enlargement sometimes masks it. It accompanies 

 many fevers, and is reckoned an unfavourable symptom, for it shows that the body 

 is not properly nourished. . 



There is another word frequently used in connection with the term symptoms 

 which we cannot pass by without notice. "We sometimes speak of a "patho- 

 gnoinonic " symptom, and by that we mean one that is characteristic of the disease. 

 Thus the peculiar eruption is pathognomonic of small-pox, and chalk-stones are 

 pathognomonic of gout. 



There is considerable difference in the mode of onset of different diseases, some 

 coming on quite suddenly, and others very gradually. A man may be on his legs 

 at a public meeting, when he suddenly has a stroke, and goes down just as if he had 

 been shot ; or, on the other hand, a man's powers may fail him so gradually that 

 it is impossible for him to say really when he first noticed anything wrong. 

 Frequently the illness is " acute," not only coming on rapidly, but being severe in 

 character and brief in duration. The great majority of cases are " chronic," the 

 symptoms setting in gradually, not being very severe, and the progress being slow 

 and protracted. A chronic disease may, however, be the sequel of an acute attack, 

 and an acute attack is not unfrequently the cause of a fatal complication in 

 chronic- < 



In many diseases, especially the acute diseases, the illness is divided into different 

 stages. For instance, a person is brought in contact with a patient suffering from 

 small-pox, but it is not till twelve days after that he feels ill, has shivering, and 

 suffers from a pain in the back. This period is called the period of latency or 

 incubation, and varies in duration in different diseases. Its existence is not limited 

 to acute diseases, for we find that it is present in many nervous affections. For 



