334 BACTEKIOLOGY OF THE EYE 



The varying results of the different authors might be due to differences in their 

 methods, the unequal virulence of the strains used for immunizing purposes, and to 

 the degree of immunity not being determined. 



De Eenzi has lately (1905) reviewed the results of the previous ten years' treat- 

 ment of pneumonia with Pane's serum, and expresses his appreciation of it. Panichi 

 similarly refers to the Tizzoni-Panichi serum, and testifies to its value. Thera- 

 peutical attempts have recently been made in pneumonia with the polyvalent 

 serum of Romer (Knauth, Deutsche Mecl. Woch., 1905, No. 12; Piissler, Deutsches 

 Archiv f. Klin. Med., 1905, Bd. Ixxxii. ; Lindenstein, Munch. Med. Woch., 1905, 

 p. 1874). The results are given by these authors as favourable, especially with 

 regard to the subjective condition. It is interesting to note that Knauth and 

 Passler gave large doses up to 60 c.cm., which were quite harmless ; while Linden- 

 stein states that 10 c.cm. given early is quite sufficient. Jiirgens (Med. Klin., 1907, 

 p. 273) reviews the question, and states that an authentic curative action in pneu- 

 monia has not yet been demonstrated. We must wait until a much larger 

 material is available before corning to any conclusion. 



The collected observations regarding ulcera serpentia are not applicable in every 

 particular to pneumonia, nor are those of pneumonia to ulcus serpens. 



The opinion we have quoted as held by Klemperer, that pneumococcal 

 serum, like diphtheric, was antitoxic, and counteracted the pneumotoxin which 

 collected in the blood, is erroneous ; on the contrary, the material is one which 

 attacks the bacteria themselves. (The substance, according to the work of 

 Wassermann, is produced in the marrow, in the blood -serum and the thyrnus, 

 to a much smaller degree in the spleen and the lymph-glands, and not at all in any 

 other organ.) The toxic power of Pneumococci is due to endotoxins, which 

 remain in the bodies of the bacteria, and therefore can only be affected by the 

 action of bactericidal substances. All the ' bactericidal ' sera in the widest sense 

 of the word are considerably less efficient than the antitoxin. 



Until recently the pneumococcal immune serum has been considered as a 

 bactericidal one, in the sense that the antibodies (amboceptors) attached to the 

 bacteria, with the assistance of the ' complements ' (alexines) derived from the body 

 of the man or animal, produced the destruction of the cocci. For such to occur it 

 is necessary that the antibodies and the complements must suit each other. On 

 account of the specific variation of different strains of Pneumococci, it is possible 

 that the serum produced by one strain will be complemented by one species of 

 animal, but not by another; and it is also possible that an amboceptor (Erlich) 

 may have an affinity to one strain, but may not possess any for a Pneumococcus of 

 another origin. 



As, however, a bacteriolytic activity has not yet been proved for pneumococcal 

 serum, either in the peritoneal cavity (analogous to the cholera experiments of 

 Pfeiffer) or in a reagent glass with the addition of the complement, we must agree 

 with Neufeld that no such bactericidal power as has been attributed to this immune 

 serum exists. The assistance of the leucocytes generally is necessary ; by phago- 

 cytosis they render harmless the bacteria previously altered by the serum. Neufeld 

 called this action ' bacteriotropic/ as it brought about the conditions under which 

 the leucocytes could attack the bacteria after the receptors of the bacterial toxin 

 were satisfied by the antibodies. 



Where a bacteriolysis from immune serum and complement was never obtained, 

 immune serum, on the other hand, immediately caused an intense phagocytosis if 

 leucocytes were present. These results tend in the direction of the well-known 

 teaching of Metschnikoff, though his opinion that the leucocytes are directly 

 stimulated to phagocytosis by the immune serum is not correct. 



These observations regarding the ' bacteriotropic activity ' of pneumococcal serum 



