One of the organs always involved in disease, in a greater or less degree, in fever, is the mucous membrane of the stomach and intestines. In synochus mitior the affection of this organ appears to be slight, and to pass away without producing any change in its structure. But that it is really diseased even in the mildest case, we have sufficient evidence in the invariable derangement which takes place in the functions of the organ throughout its whole course, from the mouth to the anus; and in the constant vitiation of its secretions and excretions. In the severer forms of fever, on the other hand, in the great majority of cases, the affection of the abdomen becomes prominent, and whenever it does so it aggravates all the other febrile symptoms, and adds greatly to the danger of the disease.

Abdominal affection exists under two forms in fever, each of which is attended with distinct and peculiar symptoms. It may be severe from the commencement, and give early and obvious indications of its existence; or it may come on at some subsequent stage of the disease, and then, although the affection be equally severe, the symptoms which denote it are materially different.

1. If the abdominal affection be severe from the commencement, in addition to the ordinary symptoms of fever, there will be present nausea, sometimes retching, and at other times vomiting. It is usual for authors to enumerate these events among the ordinary occurrences of fever; but in a case decidedly cerebral, or in a case decidedly thoracic, they are seldom present. Whenever they occur in the commencement of fever they are the certain signs of an abdominal affection more severe than ordinary; and it will be of the utmost advantage to the patient should the practitioner be aware of this, because it will teach him at once where the main force of the disease is probably to be concentrated.

2. At this early period the bowels are commonly constipated, and on inquiry it will be found that they have been so for some days previously to the attack of fever; but in a day or two after the commencement of this attack they fall into the opposite state and are looser than natural. The concurrence of nausea, retching, vomiting, and purging in the commencement of fever is a certain proof that severe abdominal affection is present, and if not actively treated and effectually checked at this early stage, it will soon render the case formidable, if not hopeless.

3. When the abdominal affection is thus early and open, it is often attended with another symptom which seldom fails to attract attention, namely, pain. Pain of the abdomen, attended with purging, completes the train of local symptoms that occurs at this early period, in the most exquisitely marked cases. It is well worthy of observation, however, that pain is by no means an invariable attendant on the other symptoms, even when the latter are very severe. Whether in these cases the affection of the nervous system be already so great as to lessen the sensibility of the organ, or whatever else may be the cause of it, the fact is certain, and it is one of great practical importance, that pain of the abdomen is not to be expected even in severe abdominal affection; and that though pain may attend upon the affection, yet the affection is often present without pain.

4. Pain of the abdomen upon pressure, and especially upon pressure in the epigastrium, is much less seldom absent than pain of which the patient spontaneously complains.

5. Pain, though it may usher in the abdominal affection, and may even be severe for the first few days, diminishes after a certain time and then ceases altogether, so that it is extremely rare, after the tenth day of fever, for instance, for the patient to complain of pain of the abdomen, even when the abdominal affection is the most intense. Such an event may happen, perhaps when the cerebral affection is more than commonly slight, but it is an exceedingly rare occurrence, and my attention has been particularly drawn to this circumstance from reflecting on the uniformity of the answers which I have obtained from patients obviously labouring under abdominal affection, on my first visit to them in the wards of the hospital. Having commonly been ill from ten to fourteen days, the abdominal affection may by this time be fully developed: on asking them whether they feel any pain in the abdomen, the answer almost invariably received is, “no.” Press gently upon the abdomen, press especially upon the epigastrium, often even in these very cases not the slightest touch can be borne. After pressure has once been made, the patient will frequently do all he can with his hand to prevent its being made a second time. So acutely sensible is he of pain on the least pressure, though wholly unconscious of pain when left to himself. Even when there is not this great degree of tenderness, pain can generally be produced by full pressure.

There is thus a remarkable coincidence between the progress of the symptoms in the abdomen and in the head. We have seen that however intense the cerebral affection, the pain of the head which accompanies it diminishes after a certain time, and in a day or two after it has begun to diminish, ceases altogether. In like manner the pain which ushers in an acute abdominal affection diminishes after a certain time, and soon wholly disappears. After this period, therefore, we should have no more indications of abdominal than we have of cerebral pain were the intestines, like the brain, enclosed in a bony case. When an organ can be touched, it gives us an additional and an invaluable means of ascertaining its morbid condition: and this is one reason why that condition is commonly so much more certainly known in surgical than in medical diseases. What the result would be, could we press the brain as we can the abdomen, after its sensibility is so much diminished as to cease to occasion pain, we do not know; but it would be a bad use indeed to make of the additional means afforded us of ascertaining the condition of the intestines, were we to allow the additional information we thus gain, to obscure our perception of the perfect analogy there is in the progress of both affections. We know that, as the disease advances in both, the pain ceases; but, in the one case, we have the means of ascertaining that there still remains preternatural tenderness on pressure, as in ordinary inflammation, which we are without the means of discovering in the other: still the important practical fact afforded by the history of both is the same, that disease having reached a certain point, the pain diminishes; and having advanced still further entirely disappears.

6. While the pain lessens or ceases as the abdominal affection advances, the purging, on the other hand, continues, often it increases. Purging, succeeding to constipation and to pain, and remaining after the subsidence of the pain, affords an infallible indication of abdominal disease.

7. Together with these decisive signs, which alone are abundantly sufficient to enable us to ascertain the presence of the affection, we have an additional and an exceedingly valuable guide in the peculiar state of the tongue. In these abdominal cases, the tongue is preternaturally red. Sometimes this increased redness is of a bright and vivid colour, and pervades the whole tongue; at others, it is confined to the edges or to the tip, and it is usually remarkably apparent in the latter. While thus vividly red, the body is often loaded with fur; the colour of the fur is often of a dirty-white or greyish colour; but, perhaps, while the edges and the tip are thus intensely red, the most usual colour observed on its body is that of a dirty yellow. In these cases, the papillæ appear much enlarged, and are seen prominent through the fur, vividly red. In this condition of the tongue it always remains moist for some time, and it is not attended with urgent thirst; but, as the intestinal disease advances, the tongue gradually becomes less vividly red and more dry, and as these changes go on, the lips and teeth often become sordid.