CHAPTER V 



THE SPECIFICITY OF HAEMOGLOBIN 



JL N many text-books of physiology there will be seen a picture of 

 crystals of the haemoglobins of several animals. The moral of the 

 picture is that these crystals differ in form. Yet within recent years 

 very little attention has been paid to their differences, possibly 

 because they were in no way linked up with the properties of the 

 haemoglobins as carriers of oxygen. 



In 1909 the Carnegie Institute published a monumental report on 

 the subject by Prof. Reichert, who held the chair of Physiology 

 in Philadelphia, and his colleague, the professor of mineralogy in the 

 same University, Dr A. S. Brown (i). The scope of the work may be 

 judged from the fact that 600 different photographs of the crystals 

 of haemoglobin from different animals are published in the hundred 

 plates at the end of the book, whilst in 338 quarto pages of letterpress 

 the properties of these crystals are tabulated and discussed. Starting 

 with the fishes, these authors go right up the vertebrate scale and 

 end with an investigation of the blood of the primates. And yet there 

 is much unsaid. There are many well-known forms of life, the haemo- 

 globin of which is not discussed. I need go no further than the frog. 

 Why? WeU, of course I can only speculate, but I suppose that they 

 could not make the haemoglobin from frog's blood crystallise. And 

 here I would like to put in a plea for the publication of negative 

 results. At the present time, when the claims on the space in journals 

 are very great, it is natural to pass over experiments which have 

 led to no positive result. Moreover a man of modest disposition 

 feels that he is making rather a "fuss about nothing" in publishing 

 his negative experiences, but all that is no comfort to his successor 

 who, after much toil and labour, arrives at precisely the same point, 

 only to be told that A, B or C had travelled the same road before him 

 and with the same result. In the present case it would be very 

 interesting to know what forms of life had yielded haemoglobin which 

 Reichert and Brown had found impossible to crystallise. The bare 

 allusion to these facts brings out two properties, in addition to 

 crystalline form, in which the different animals' haemoglobins differ, 

 namely, solubility and ease of crystallisation. Solubility will be dealt 



