248 EXPEEIMENTAL INVESTIGATION OF THE ACTION OF MEDICINES. 



to the middle part on which the ohject lies, and thus warm it to 

 any desired temperature. The drop of blood must be placed on 

 a jjiece of glass 3 J inches long and 2-J broad, whicli is then laid 

 on the warm stage. The drop is next covered by a thin 

 glass, and over all is put the lower part of a lamp-cylinder, 

 through whose upper end the tube of the microscope slides, and 

 round whose interior is put a piece of moist blotting-paper to 

 prevent evaporation from the blood. The drug is applied as 

 with Strieker's stage. Solutions of corrosive sublimate and 

 veratria, even in very minute quantity, stop the movements of 

 the white blood-corpuscles, but neither is so active as quinine. 

 Strychnia is rather less powerful than any of these, and many 

 other alkaloids much less so. 



Action on Inflammation. — During inflammation, the white 

 blood-corpuscles are very active, and crawl through the walls 

 of the capillaries in much greater numbers than usual. It is, 

 therefore, interesting to inquire what will be the effect on this 

 of any drug that stops their motions. Tor this purpose we 

 curarise a frog, and lay it on a large plate of cork with a hole 

 at one side and another piece of cork J inch high at the 

 other. We fix the body of the frog to the raised piece, open its 

 abdomen with a pair of scissors, draw out the intestines, and 

 fasten the mesentery with very fine pins over the hole. In an 

 hour and a half or two hours afterwards white corpuscles come 

 rapidly out of the vessels and wander over the field. We may 

 then inject our drug into the circulation or apply it locally to 

 the mesentery. 



Binz states that, when he injected quinine into the circula- 

 tion, the number of corpuscles in the vessels became diminished, 

 and they ceased to wander out, while those already out con- 

 tinued to wander further, so that, instead of being evenly 

 distributed over the field, they left a clear space round the 

 outside of the vessel, in which few were to be seen. If, on the 

 other hand, it be applied locally, the corpuscles which are 

 already out stop moving, while those in the vessel continue to 

 migrate, and thus, instead of a clear space, a dense accumula- 

 tion of corpuscles forms round the vessel. In order to produce 

 this effect, yto"o o^^^ ^° tot^o ^^^ ^^ ^^^^ animal's weight of quinine 



