H^EMATIN. 299 



A carbo-hydrate has been found in some of the lower classes of 

 animals whose composition and properties are very similar to those 

 of the vegetable principle, cellulose. C. Schmidt* discovered it in 

 the mantel of Phallusia mammillaris, one of the mollusca belonging 

 to the Tunicata ; and Lowig and Kollikerf have subsequently recog- 

 nised it in the cartilaginous capsule of the simple Ascidiee, in the 

 leathery mantle of the Cynthiae, and in the outer tube of the Salpee. 

 The relation which this substance bears to chitin as well as to the 

 animal organism generally, will be noticed in our remarks on chitin. 



COLOURING MATTERS. 



Unfortunately, even less is known of the chemical nature of 

 the animal than of the vegetable pigments, so that we must still 

 retain the irrational system of arranging them according to colour. 



H^MATIN. C 44 H 22 N 3 O 6 Fe. 



Chemical Relations. 



Properties. This substance is regarded as the peculiar red 

 pigment of the blood-corpuscles ; but unfortunately it is by no 

 means certain whether it is a product of metamorphosis of the true 

 colouring matter of the blood, or whether the substance prepared 

 by us only bears the same sort of relation to that which exists in 

 the blood-corpuscles as coagulated albumen bears to that principle 

 in its fluid state. We cannot isolate it in its soluble state from 

 the globulin of the blood-corpuscles ; hence we are only acquainted 

 with it in its coagulated (and essentially modified) condition. In 

 a state of purity it occurs as a dark brown, slightly lustrous mass, 

 which, on trituration, adheres to the pestle ; it is devoid of taste and 

 smell, and is insoluble in water, alcohol, ether, acetate of oxide of 

 ethyl, and fatty and volatile oils : Mulder, however, regards it as 

 slightly soluble in fatty and ethereal oils. 



Hsematin dissolves very readily in weak alcohol to which sul- 



* Zu vergl. Physiol. der wirbellosen Thiere. 1845. S. 62 [or Taylor's Scientific 

 Memoirs, vol. 5, p. 34. G. E. D.] 



f Ann. de Scienc. Nat. 3 Se'r. T. 5, pp. 193-232. 



