LABORATORY MANUAL OF PHYSIOLOGY. 



changes is said to be lytic for those particular cells upon which it 

 acts. 



It has been found that a serum which is not normally lytic for 

 the blood of a certain animal, may, through a so-called adaptive 

 process, be made to acquire such properties. This may be de- 

 monstrated in the following series of experiments : 



4. The serum of the guinea-pig is not normally lytic for the cells 

 of rabbit's blood. Verify this statement by mixing equal parts of 

 rabbit's blood and guinea-pig serum and examining, microscopi- 

 cally, for laking. 



5. A guinea-pig is adapted for rabbit's serum in the following 

 manner: 5 c.c. of rabbit's blood is injected into the abdominal cav- 

 ity of a guinea-pig every third day until five injections have been 

 given. The animal should be weighed, daily, and the tempera- 

 ture recorded. If the reaction following the injection be too 

 severe, the quantity must be reduced. The quantity of the injec- 

 tion may then be increased providing that there is no decrease in 

 weight or marked variation in temperature, and continued until 

 ten injections are completed. 



The pig is then bled, the blood allowed to clot, and the serum 

 collected. 



Bleed a rabbit. Collect the blood in a test tube containing three 

 times the volume of o.8-per-cent NaCl solution. 



(a) Take a small portion of the diluted blood and add the same 

 amount of the adapted pig's serum. 



(b) To a second portion of rabbit's ' blood add equal parts of 

 guinea-pig's serum which has not been adapted. 



(c) To a third portion of blood, add some of the adapted 

 serum which has been, previously, heated to 60 C. for thirty 

 minutes. 



(d) To a fourth portion of blood add equal parts of the adapted 

 serum which has been heated and serum from a guinea-pig which 

 has not been adapted. 



Compare the dilute rabbit's blood, untreated, with tube (a), tubes 

 (&), (c), and (d). Examine slides from each under the microscope. 



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