or not at all, then one further test must be applied to itnamely, Pfeiffer's test. This consists in injecting peritoneum of a guinea-pig a lo-times fatal dose of the bacillus in question, together with a very small quantity (o.ooi c.cm. may be quite sufficient) of typhoid serum a highly-immunised animal. If the bacillus in question be the typhoid bacillus, then while a control animal injected only with the bacillus will die this animal will recover, the bacilli being converted first into

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... r masses (Pfeiffer's phenomenon) and then gradually disappearing under the influence of the lysogenic properties of the serum. serum, however, is specific, and can therefore only protect, in minute doses, against the corresponding micro-organism. If, therefore, the bacillus in question be not the typhoid bacillus, but some variety of bacillus coli, the animal will infallibly die like the control animal. This test is of the highest portance for if properly performed a positive result is infallible. The test should always be applied in any case there can be doubt as to the nature of the micro-organism, If for example, a bacillus which should fail to agglutinate nevertheless should react like the typhoid bacillus test, then we must accept it as the latter. [In regard to the typhoid bacillus as a saprophyte, the lecturer remarked that we must allow that so far there was no bactericidal power, it is likely that such bacilli as do not succeed ing shelter in some viscus are rapidly destroyed. This not occur to the same extent in fatal cases (perforation similar cases being excluded), for often it is owing tients failing to acquire this power that a fatal termination sues, and onithis fact doubtless in part depends the ease with which the bacilli can be demonstrated in the blood death. We may believe, therefore, as indeed expect from the distribution of the bacillus in the the micro-organisms pass into the blood in all cases fever. They are, however, rapidly eliminated from various organs or destroyed. In rarer cases, on the probably always fa,tal, when the blood fails to acquire cidal properties, the typhoid bacilli may develop,therein, be found after death in considerable numbers. THE TYPHOID ERUPTION. It is obvious from the facts brought forward from being merely an intestinal disease. Bearing in interesting to consider the relation of the bacilli t"e roseolous eruption characteristic of the illness. The early observers for the most part were unable presence of the bacilli in this lesion. Thus Wiltschur,s Seitz,4 mann,5 Merkel and Goldschmidt,5 and others experiments all obtained negative results, while Rutimeyer7 tive result in six observations. In the light of these statemesn of Neuhaus,8 made as long ago as r886, that he had positiveresults In I5 cases, was generallyreceived with incredulity. said, therefore, that until quite recently the received the si inyyphidffe r were not due to a local typhoid bacil, probably due to the absorption typhoid, toxins into the general circulation. Observers, however, were not entirely satisfied continued working at the subject. In I 889 Thiemich9 reported that bacilli in the spots in three cases out of seven, while I899 the important paper by Neufeld,iO which apparently crepancies between the results of various observers. that if the bacilli really were the cause it was evident they to obtain their foothold in the skin and subcutaneous short time, otherwise the spots themselves would so;fleeftgi; APRIL 7, 1900.]