APPENDIX. 



335 



and are in length about equal to the diameter of a red cor- 

 puscle, sometimes larger. The round forms are smaller than 

 a red corpuscle, with the pigment arranged centrally in a 

 ring. They may become flagellated after the blood has re- 

 mained outside the body for some minutes. Any of the extra- 

 cellular bodies may show remnants of the red corpuscle at- 

 tached to its side, like a bib. The extracellular forms are 

 concerned in the cycle of development of the organism in the 

 mosquito, and are sterile in the human body. They are ex- 

 ceedingly resistant to quinine and may continue in the blood 

 for long periods of time. 



Melaniferous leukocytes are seen in the blood, being espe- 

 cially abundant after the paroxysm in all forms of malarial 

 infection.* These are phagocytes which have taken up the 

 pigment granules liberated by the disintegration of the erythro- 

 cytes. 



Small-pox and Vaccinia. — Micrococci of various sorts 

 have been found in the pustules of small-pox and vaccinia, 

 but indicate only a secondary infection. Other microorgan- 

 isms have been described. The most important are certain 

 bodies often considered protozoa. In both small-pox and 

 vaccinia small, round homogeneous bodies, 2 to 4 // in diam- 

 eter, have been found in the epithelial cells of the vesicles. 

 Inoculation of vaccine lymph into the rabbit's cornea leads to 

 the production of similar bodies in the epithelial cells of the 

 cornea. W. Reef found small ameboid bodies in the blood 

 in cases of small-pox and vaccinia. Vaccine virus that has been 

 filtered through the Chamberland or Berkefeld filter is no 

 longer active. From this it may be presumed that the organ- 

 ism causing it is not too small to be seen with the microscope. 



Councilman, Magrath and Brickerhoff,J as a result of 



* See also Ewing. Journal Experimental Medicine. Vols. V. and VI. 



^Journal Experimental Medicine. Vol. II. P. 515- See also Anna Wil- 

 liams and Floumoy, and W. H. Park. New York University Bulletin Medical 

 Sciences. Vol. II. October, 1902. 



J Journal Medical Research. Vol. IX. May, 1903. 



