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XIII. — On some Appearances in the Blood of Veriehrated Animals 

 with reference to the occurrence of Bacteria therein. 



By G. F. DowDESWELL, M.A., F.K.M.S., &c. 



{Read 11th June, 1884.) 



The occurrence normally, of micro-organisms in the blood and 

 tissues of healthy animals, has been the subject of many observa- 

 tions, in some instances with contradictory results. It is, however, 

 now well established that, both in man and other animals, they 

 are constantly present in certain situations, not only in the 

 mouth and lower intestine, but in some cases at least, in the liver 

 and pancreas ; on the other hand it has been shown that in the 

 blood they are not usually present in a state of health. To deter- 

 mine this latter point microscopical examination is inadequate, inas- 

 much as mere negative observations are inconclusive, and the ques- 

 tion has been decided by physiological experiment, viz, by taking 

 blood from the heart or vessels, with precautions against contami- 

 nation, when it is found that it may be preserved indefinitely, free 

 from septic changes ; and even in some instances, as has been 

 demonstrated in King's College by Professor Lister, without 

 coagulation. 



In some pathological conditions — in certain infective diseases, 

 — as is now well known, micro-organisms are found constantly 

 present in the blood, and in a few cases are shown to constitute the 

 true contagium, the actual materies morhi. It is possible too, that 

 in other conditions not yet investigated — as for instance in a tem- 

 porary access of fever — they may appear here, starting from those 

 situations in which they are normally present, and again shortly 

 di.sappear. For the determination of the question of their occur- 

 rence in these situations, it is essential that such other bodies as 

 may be, and have been, in some instances mistaken for them, should 

 be well known. 



The appearances in the blood which I have to record to-night 

 have been already described by myself or others, and I have but 

 little that is new on the subject now to offer. Mistakes, how- 

 ever, that have been made — in one case in a report published quite 

 recently — show that these phenomena are by no means generally 

 known or recognized. 



1. Max Schultze's Corpuscles. — The first instance to bo here 

 mentioned is, that in the blood of man and many animals, besides 

 the red and white corpuscles there are present normally, though 

 in very variable numbers, small corpuscular bodies, the nature of 

 wljich has been the subject of groat diversity of opinion, and is 

 far from being as yet determined. These are known as Max 



