386 



COMPARATIVE PHYSIOLOGY. 



solution, may be added drop by drop till changes in the spec- 

 trum in the form of dark bands appear. By gradually increas- 

 ing the quantity, ap- 

 pearances like those fig- 

 ured below may be ob- 

 served, though, of course, 

 much will depend on the 

 thickness of the layer of 

 fluid as to the quantity 

 to be added before a par- 

 ticular band comes into 

 view. 



When wishing to be 

 precise, we speak of the 

 most highly oxidized 

 form of haemoglobin as 

 oxy-haemoglobin (0-H), 

 and the reduced form as 

 haemoglobin simply, or 

 reduced haemoglobin (H) . 

 By a comparison of 

 the spectra it will be seen 

 that the bands of oxy- 

 haemoglobin lie between 

 the D and E lines ; that 

 the left band near D is 

 always the most definite 

 in outline and the most 

 pronounced in every re- 

 spect except breadth ; that it is in weak solutions the first to ap- 

 pear, and the last to disappear on reduction ; that there are two 

 instances in which there may be a single band from haemoglo- 

 bin — in the one case when the solution is very dilute and when 

 it is very concentrated. These need never be mistaken for each 

 other nor for the band of reduced haemoglobin. The latter is a 

 hazy broad band with comparatively indistinct outlines, and 

 darkest in the middle. 



It will be further noticed that in all these instances, apart 

 from the bands, the spectrum is otherwise modified at .each 

 end, so that the darker the more centrally placed characteristic 

 bands, the more is the light at the same time cut off at each 

 end of the speetrum. 



Fig. 307.— Crystallized hemoglobin (Gautier) 

 crystals from venons blood of man; e, 

 blood of cat; d, of Guinea-pig; ^, of marmot; 

 /, of squirrel. 



, from 



