INFLAMMATION AND LEUCOCYTE RESPONSE 67 



duced a leueocytosis. Menkin (1940), however, reports tliat the 

 intravenous injection of simihir or slightly higher amounts into 

 dogs failed to alter appreciably the leucocyte count. 



In connection with his studies on inflammation, Menkin (1936, 

 1938, 1939, 1940) has investigated experimentally the various phe- 

 nomena associated with phagocytosis mentioned earlier in this sec- 

 tion. His results may be summarized as follows : 



1. He has obtained a crystalline nitrogenous substance from in- 

 flammatory exudates which increases capillary permeability and 

 causes the migration of leucocytes through the vessel walls into the 

 tissues. AYhile it exhibits chemotaxic properties it will not pro- 

 duce a leueocytosis in either the dog or the rabbit. This substance 

 is called "leucotaxine." 



2. He has found a leiicocytods-promolinfi factor in inflammatory 

 exudates that causes a rise in the level of leucocytes in dogs. It 

 stimulates the bone marroAV causing a *' shift to the left" in the 

 hemogram. Tliis factor is thermolabile (inactivated at 60° C.) and 

 there is some evidence to indicate its being either a globulin or 

 associated with the globulin fraction. 



3. Menkin reports that histamine, adenosine, blood serum, sterile 

 broth and cultures of Staphylococcus aureus are all ineffective in 

 causing an increase of the level of leucocytes in the circulation. 



4. The leucocyte-promoting factor causes a prompt leueocytosis 

 whereas nucleic acid produces a delayed reaction. 



It is suggested that the student read a few of the papers bearing 

 upon the Arneth and Schilling counts Avhich are included in the 

 list of supplementary references. From a survey of the literature 

 and some personal experience, one feels warranted in suggesting 

 Ihat tlie student weigh carefully tlie claims of those authors who 

 feel that any method of classification of white cells is infallible iu 

 prognosis. While the Schilling count is often of value, it is also at 

 times misleading. It is well to remember that even accurate lab- 

 oratory findings must be interpreted by a trained, intelligent indi- 

 vidual with considerable clinical experience. 



References 



Cunningham, R. S.. Sabiii, F. R., and Doan. C. A. : The Development of 

 LeucocA"te.s, Lymphocytes and Monocytes from a Specific Stem Cell in 

 Adult Tissue.". Carnesrie Inst. Contributions to Embryology 16: 229, 

 3925. 



