INVERTEBEATA, CRYPTOGAMIAj MICROSCOPY, ETC. 755 



body, surrounding tlie red corpuscles and absolutely filling tbe white. 

 Even -^^j drop of the blood tlius affected was able to communicate the 

 disease to another mouse, and the disease was, in fact, carried through 

 seventeen generations. There seems little doubt that the bacilli are 

 the actual contagium of this form of traumatic septica3mia. It is a 

 curious circumstance that field-mice and rabbits were not suscej)tible 

 to the disease, 



2. Progressive Tissue-necrosis (Gangrene) in Mice. — In mice injected 

 with decomposing blood there were sometimes found at the place of 

 injection (in the subcutaneous tissue) micrococci, as well as the 

 regular bacilli of septictemia. These micrococci had a diameter of 

 • 5 /x, multiplied rapidly, and showed a great tendency to the forma- 

 tion of " chains." Lymph from the subcutaneous tissue infested with 

 these was injected into a mouse's ear. The micrococcus-chains soon 

 multiplied so fast as to interpenetrate the whole ear, the tissue of 

 which became so changed as to be hardly recognizable ; cartilage cells 

 looked pale, as if treated with potash, and blood and connective-tissue 

 corpuscles were no longer to be seen. It seems clear that the septi- 

 caBmia-bacillus is a necessary forerunner of the gangrene-micrococcus. 

 An interesting pure-culture experiment was tried. Field-mice, which, 

 as stated above, are not susceptible to septicaemia, were injected with 

 fluid containing both bacilli and micrococci. The former had no 

 effect, the latter multiplied and caused death, and from the animals so 

 affected both field and house mice could now be inoculated, the 

 result being always gangrene and never septicaemia. 



3. Progressive Abscess-formation in Babbits. — Rabbits were injected 

 with putrid blood. A flat, hard, lenticular infiltration was gradually 

 formed at the place of injection, producing at last a fatal abscess in 

 the subcutaneous tissue. The abscess was covered by a thin layer of 

 micrococcus-zoogloea ; its cheesy contents were finely granular, and 

 contained no bacteria, but were probably derived from the zoogloea 

 and from the enclosed dead tissues. The individual micrococci were 

 0-15 w in diameter. The blood of rabbits dying from this disease 

 produced no infection, but the disease v/as communicated by injecting 

 a little of the interior of the abscess rubbed up in water. 



4. Pyismia in Rabbits. — A rabbit was injected with fluid obtained 

 by macerating mouse-skin in water. A purulent infiltration of the 

 subcutaneous tissue resulted, accompanied by swelling of the spleen, 

 morbid changes in lungs and liver, and peritonitis. Micrococci 

 abounded in the affected places, occurring in the blood-vessels sur- 

 rounding the corpuscles, and forming accumulations which some- 

 times quite obstructed the lumen. These micrococci are distinguished 

 from those of gangrene and abscesses by not forming chains or 

 zooglcea, and by their size (0 • 25 ^a). For inoculation, J^ of a drop 

 was sufficient, but not y^fny 



5. Septiccemia in Babbits. — The animals were injected with a 

 putrid infusion of meat. A purulent accumulation (jauchige Vereiter- 

 ung) took place, and the subcutaneous tissue in the neighbourhood 

 became filled with a watery fluid, containing large oval micrococci 

 (diameter 0-8 to 1 1^), \yhich also occurred in the kidney and spleen. 



