But the statements regarding the condition of the spleen in influenza are remarkably contradictory.

While the pathologists, Birch-Hirschfeld "generally found no changes in the spleen," and Jiirgens "had seen no splenic tumor," Rib bert, on the other hand, found "the spleen occasionally enlarged"to several times its ordinary volume, and in all (8) some enlargement." In agreement with this author and other pathologists (Wallis) we too occasionally observed marked increase in the size of the spleen in a number of postmortem examinations; so, too, Drasche found "in all influenza cadavers acute and sometimes considerable enlargement of the spleen," while Winogradow found it only twice in 13 autopsies.

Kuskow has studied the pathologic condition of the spleen in influenza most thoroughly. He found it enlarged 12 times among 40 autopsies, generally but slightly; in the remaining 28 cases the spleen was smaller and "often considerably lessened in size." The following are the principal characteristics of the "typical influenza spleen": The capsule is shriveled, the pulp is gray or dirty violet, of the consistence of a rotten plum, and studded with dark red areas. Microscopically there is swelling of the endothelium of the veins and arteries, so that the lumen of the small arteries is often entirely obliterated. In other places one finds thrombi in the veins and capillaries. Together with these changes one finds blood extravasations and tissue necrosis of both the trabecular and of the pulp. Only rarely are micro organisms met with and then only in small numbers.

Very different and even diametrically opposed are the statements of clinicians regarding the size of the spleen in influenza. Strumpell, Fleischer, Rosenbach, Runeberg, Regnier and Comby, Swajser and Dunin, Begejawlensky could never find splenic enlargement; Peiper could find it but twice among 217 cases; Vesterdahl but once among 73 patients; and Holmberg and Linden but twice. Very small percentages are recorded by Meckel (Nuremberg) and Hofler (Tolz), namely, 2 per cent.; H. Rieder (Munich), 3 per cent.; Stintzing and A. Frankel, 5 per cent.; and Golowin (St. Petersburg), 8 per cent. The condition of the spleen attracted the attention of English observers but little. The statistics of Bristowe, Preston, Robertson, and Elkins, to which such frequent allusion has already been made, contain no mention of the spleen in influenza. All that I could find can be embraced in the sentence: "Enlargement of the spleen in a small and uncertain proportion of the cases" (Thompson).

In marked contrast to these statements are numerous others, according to which the influenzal splenomegaly is of very frequent occurrence.

Sokolow and Kernig describe enlargement of the spleen as a constant feature. It was observed in the city hospital at Dresden in 80 per cent, of the cases; in Hamburg, in 56 per cent.; by Baumler (Freiburg), in 63.5 per cent.; and by Schnaubert (Petersburg), in 39 per cent. Goll (Zurich) describes it as of very frequent occurrence. An intermediate position is taken by the following authors. Enlargement of the spleen was found by Guggenheim (Wiirzburg) in 25 per cent, of cases; by Anton (Wiirzburg), in 16 per cent.; and by Aufrecht, in about 20 per cent. We found it in 14 per cent., and Gutmann (Nuremberg), in 11 per cent.; Krehl and Fischel each in 10 per cent.

In the French reports the frequency of enlargement of the spleen is almost invariably mentioned by Potain, Chantemesse, Guyot, G. See, and Mangoubi.*

The diametrically opposed statements concerning the spleen can by no means be excused by the fact that the cardinal question, " How many centimeters must the spleen measure to be considered enlarged?" cannot be answered with exactness, for the normal size of the spleen varies. A volumetrically normal or even enlarged spleen, if spheric, may appear small upon percussion, while a very flat, disk like spleen, of normal size, may, under the same circumstances, appear enlarged. The pathologist is in a better position to judge by the total volume of the spleen, and may thus recognize that a volumetrically normal sized spleen is "swollen" by other criteria (stretching of the capsule, turgescence of the organ). But the clinician must be careful not to attempt too minute deductions from the percussion area of the spleen as measured in centimeters.

* "Splenomegalie grippale," "These de Paris," 1895.

Attempts have been made to explain the contradictions just mentioned regarding the spleen in influenza. Kuskow believes that the variance in views is due to the different virulence of influenza in different places. Others believe that the accumulation of complicated cases, especially those with pneumonia, has given rise to the aggregation of cases with enlargement of the spleen. Another explanation often put forward is that enlargement of the spleen occurs frequently in the gastro intestinal form, and when this form prevailed, there too splenomegaly was often found. But all these attempts at explanation are inadequate and do not go to the root of the matter. As a matter of fact, these extremely contradictory views are the result of nothing else than the attribution of an exaggerated value to percussion, and the consequent assumption of an increase in the size of the spleen from percussion, when more cautious observers would hesitate to draw this conclusion. On the other hand, some modern observers go too far in depreciating the value of percussion of the spleen when they lay so little stress on the result of this excellent method of examination as to consider only a palpable spleen as enlarged.*

Baumler, in 122 cases of splenic enlargement, found the spleen palpable in 23 cases, and in the remaining 99 cases the enlargement was demonstrable only by percussion.

We found the spleen enlarged in 62 cases. Among these the organ was plainly palpable in 49 cases; and in 13 cases the enlargement could be demonstrated only by percussion.

The relations of the palpable spleens to those found enlarged only by percussion were as follows:

By Baumler...........19.0 per cent, palpable; 81.0 per cent, enlargement on percussion.

By us..................79.0 " " " 21.0 per cent, enlargement on percussion.

By Anton (Wiirzburg). .87.5 " " " 12.5 per cent, enlargement on percussion.

These figures explain, without any further comment, why one observer could find it in 63 per cent., and the others only in 14 and 16 per cent., of enlargement of the spleen.

The contradictory experiences of the pathologists are easily explained. The pathologic material was provided principally by those who had survived the true influenza attack and who had subsequently died from complications or sequelae, and considering also the slight mortality of influenza, the pathologic material for observation was everywhere very meager. When such conditions exist, the results are very irregular.

Unexplained, however, is the fact that numerous clinical observers never found an enlargement of the spleen in spite of the large number of cases which came under their observation.

Parotitis, an occasional complication of all infectious diseases, also occurs occasionally in influenza. It was recorded, so far back as the epidemics of 1580, 1732-1733, and all the following ones, occasionally in conjunction with orchitis (compare p. 684) or with erysipelas of the face. In these cases there is undoubtedly "mixed infection." In all collective investigations of the most recent pandemic, parotitis is mentioned as a rare complication. Of the 55,263 patients in the German army, 12 showed this complication; of the 3185 reporters of the German investigation, 37 mentioned parotitis. Fiessinger and we ourselves early called attention to this complication.

* Compare our influenza lectures, p. 34.