40 HEMOGLOBIN 



same genus, and where conditions are favourable they can pre- 

 sumably all be developed in each species. 



Some interesting facts which may bear upon the relations of 

 different species and genera to one another are recorded. Among the 

 primates for instance, the a-oxyhsemoglobin of the baboon and of 

 man are strikingly alike; the ^-oxyhsemoglobin of the baboon has 

 no counterpart in man but the y-oxyheemoglobin in the two are 

 similar. 



Among the rats : 



It has been generally stated in the zoologies that the white rat is an albino of the 

 black rat. From our examination of the crystals it is evident that the white rat is 

 closely related to the brown or Norway rat, but it cannot be closely related to the 

 black or Alexandrine rat. 



Again, by some zoologists the bats have been placed among the 

 primates and the relationship of the groups has been claimed by a 

 number of zoologists. The crystals of oxy haemoglobin from the brown 

 bat do show a considerable resemblance to the crystals of oxyhaemo- 

 globin of the genus Papio, but on the other hand the fruit-bat 

 examined showed quite a different type of crystal. 



Specific differences in the solubilities of the haemoglobins of dif- 

 ferent animals have been the subject of a fascinating research by 

 Landsteiner and Heidelberger(2). These differences are no less striking 

 than the differences of crystalline form, and are no doubt related to 

 the ease with which haemoglobin crystallises. 



From the solubility let us pass to the spectrum. The haemoglobin 

 spectra of relatively few forms of life have been studied ; but of such 

 as have, no two species yield exactly the same spectrum. 



It had been shown indeed by Sorby(4) that the spectra of all 

 haemoglobins were not the same. The instance which he adduced is 

 the disparity between the haemoglobin of the snail Planorbis and 

 that of vertebrate blood. The following is his statement of the 

 positions of the centres (not necessarily the positions of maximum 

 density) of the bands: 



Centres of bands * 



(Angstrom units) 

 a p 



Vertebrate oxy haemoglobin ... 5810 5450 



Planorbis oxy haemoglobin ... 5780 5425 



The position of the a-band differed in the two forms by about 30 

 Angstrom units, and of the j3-band by about 25. Gamgee (5) denied this 

 difference. It is only to be supposed that the instruments of former 



