BLOOD. 



To the solution, add some reducing agent. Can reduced hae- 

 moglobin be obtained from methaemoglobin ? 



8. Hsematoporphyrin (haematin freed from iron). Add con- 

 centrated sulphuric acid to some defibrinated blood in a test 

 tube. Filter through asbestos. Examine the spectrum of this 

 solution. 



9. Haematin. Prepare solutions of acid haematin, alkali 

 haematin, ethereal solutions, acid alcohol solutions. Observe the 

 spectra, comparing them with each other and with the spectra of 

 the other haemoglobin derivatives, studied above. 



Drawings should be made of all the absorption spectra that you 

 have seen, and these should be compared with the table of spectra 

 in the text-book or hanging in the laboratory. 



IX. GLOBULICIDAL ACTION OF SERUM. 



1. Mix, in a small test tube, equal quantities of rabbit's 

 blood and dog's blood serum. Let this stand for twenty to 

 thirty minutes and then observe. Is there any change in the 

 color of the mixture? Observe with reflected and trans- 

 mitted light. Compare with blood that has been diluted with 

 water. Place a drop on a slide and examine with the micro- 

 scope. Compare this with a fresh sample of undiluted rabbit's 

 blood. 



2. Heat the dog's serum to 60 C. for ten to fifteen minutes 

 and repeat experiment i. 



3. Repeat experiment i, using rabbit's serum in place of dog's 

 serum, and dog's blood in place of rabbit's blood. Do the same 

 phenomena occur ? 



The sera of certain animals, when mixed with the blood of cer- 

 tain other species, cause a destruction of the cellular elements with 

 a consequent escape of the haemoglobin and its solution in the 

 liquid portion of the mixture; or, in other words, laking occurs. 

 This property is true for other cells than blood, so that, 

 broadly, it is known as cytolysis. More specifically, in the case 

 of blood, it is known as haemolysis, and the serum causing such 



[77] 



