80 H. C. SORBY. 



lijematin into a closely related product. Much light is thrown 

 on this question by the action of potassic permanganate. On 

 adding a small quantity to normal haematin formed by boiling 

 human blood AAith dilute ammonia, it is first changed into a 

 modification which, when deoxidized, gives similar bands in 

 exactly the same situation as those in the solution kept long 

 sealed up in a tube ; but yet there is such a decided dif- 

 ference in their width as to make it probable that the two 

 products are not exactly the same substance. The facts do, 

 however, prove that normal haematin can be changed by 

 slight oxidization into an analogous substance, giving the 

 absorption bands somewhat nearer the blue end of the 

 spectrum. On adding still more permanganate this is still 

 further and very completely changed into an entirely new 

 product, Avhich when deoxidized gives a well-marked band 

 in the yellow, having its centre at wave length 587. 



Now, on treating the hsematin of the bile of Helix with 

 potassium permanganate, it is in the first instance so changed 

 as to give on deoxidization exactly the same spectrum as 

 normal hsematin, with the bands in exactly the same position ; 

 and further action of the permanganate alters it into the 

 ether modification already named. I have not, however, 

 succeeded in preparing the product giving the band in the 

 yellow, probably on account of the presence of so much of 

 more easily oxidized substances, which make the bile so thick 

 and gummy. It thus appears almost certain that the haematin 

 of the bile of Helix can be changed into normal haematin by 

 a process of oxidization, and that this change modifies both 

 the spectrum and the affinity for loosely combined oxygen. 

 We may, therefore, very reasonably expect to meet with this 

 normal modification in some of the organs of the living ani- 

 mals, and, in fact, 1 think it very probably does occur in the 

 muscles of the foot and elsewhere, since the absorption band 

 is certainly nearer to the blue end and nearly corresponds 

 with that of normal haematin. I have, however, not yet 

 proved this to my entire satisfaction, for want of proper 

 material and good direct sunlight since I perceived the 

 importance of the question. 



The amount of haematin found in different species and 

 genera of pulmoniferous molluscs difliers very much. In 

 Testicella, Pupa, and Clausilia, there was so little as to make 

 its presence very doubtful. The amount in Limnaa is small, 

 but yet very decided, and is much greater in Helix, Zonites, 

 Limax, and Cyclostoma. In all these its presence is usually 

 most decided in the liver, but yet it is not confined to that 

 organ. I have not been able to detect it in the blood itself, 



