The special function of the spleen has never been clearly determined; like other glands its action is to modify the constitution of the blood. The precise alteration which is effected by its passage through splenic tissue has not been discovered. The spleen may be removed from a dog without its loss producing any permanent injury. The experiment has been frequently performed, and among the most constant effects noted are increase of appetite and an unnatural ferocity of disposition.

The spleen cannot therefore be regarded as a single organ, but as associated with others which may completely or to a great extent perform its function after removal.

Acute inflammation of the spleen or splenitis is an exceedingly rare affection. The symptoms which have been observed are restlessness, tenderness over the organ, some fever, loss of appetite, vomiting, great thirst, and as Youatt observes, " shivering, the ears cold, the eyes unnaturally protuberant, the nostrils dilated, the flanks agitated, the respiration accelerated, and the mucous membrane pale". The same author mentions a discharge of a yellow, frothy mucus by vomiting. By this it might be implied that in those cases an abscess had formed in the spleen and the pus was expelled by vomiting.

The disease will rarely ever be diagnosed during life, and were it, the general principles of treatment would be much the same as in acute inflammations of other organs similar in structure.

In certain diseases of the general system, and in some affections of other organs the spleen becomes enlarged for a time and then returns to its normal size.

Chronic enlargement of this gland, unless it be greatly increased in size, is rarely attended with any symptoms to indicate the condition. Were it to be discovered and clearly diagnosed the treatment would be symptom, atic, and the same as in chronic hepatitis.

The spleen takes on degenerative changes in common with the liver, but a consideration of them can be of no possible interest or profit to the general reader.