448 EXPERIMENTAL PHARMACOLOGY 



diameter in the side nearest the microscope. This hole 

 should be near the middle of the length of the board and 

 about one-fourth inch from the side of the board (next to 

 the microscope). A cork is passed into the hole (tightly) 

 and then a second hole about one -half inch in diameter is 

 bored through the cork so that the mesentery of the frog 

 can be stretched out over the hole in the cork and thus 

 brought under the objective of the microscope. Pin down 

 the loop of the intestine to the upper surface of the cork and 

 thus secure a flat surface of the mesentery for observations. 

 The upper surface of the cork should be about one-fourth 

 inch above the surface of the board. Use the low p<nver ob- 

 jective and observe the blood flow through the mesenteric 

 capillaries. Examine the white corpuscles carefully. Ob- 

 serve how they move along next to the capillary walls or 

 pass out slowly into the tissues. Do you see any lympho- 

 cytes? The exposure and manipulation of the tissues of the 

 mesentery will produce sufficient inflammation to cause an 

 accumulation of leucocytes in the area involved. After you 

 have fully familiarized yourself with the appearance and 

 action of these leucocytes then inject into the anterior lymph 

 yac of the animal two cubic centimeters of quinine hydro- 

 chloride solution (one cubic centimeter equals ten milli- 

 grams) and watch the actions and distribution of the leu- 

 cocytes as the drug is absorbed. Do the white corpuscles 

 still cling to the lining of the vessels, or do they pass out 

 into the neighboring tissues? What conclusions can you 

 draw? AVliat relation does the action of the quinine on the 

 white corpuscles bear to the action of quinine on the plas- 

 modium of malarial fever? "What general conclusions can 

 you draw from the experiment ? 



Quinine is often injected intravenously in severe cases of 

 malarial infection in man. This form of treatment is effec- 

 tive, and rapid results may be obtained. From the above 

 experiment what action do you infer the quinine thus thrown 

 rapidly into the blood will have on malarial organisms (pro- 

 vided the concentration of the drug is great enough) ? 



