86 DR. J. W. JENKIXSON ON THE [Feb. 6 



as follows : — The cells in question have outwardly- protruding 

 amoeboid processes, by which they engulf the corpuscles (PI. III. 

 figs. 1-3) ; the ingested corpuscles are often so numerous as to 

 almost entirely fill the body of the cell. Inside the cell the 

 corpuscles — often aggregated in small clumps (fig. 3)- — -become 

 gradually paler, and change their staining reaction and their form. 

 In picro-nigrosin the freshly-ingested corpuscles, like those 

 outside, take up the picric acid, but gradually gain a stronger 

 affinity for the nigrosin, and stain blue or grey ; at the same time 

 their shape becomes irregular. These irregular masses seem to be 

 enclosed in small cavities or food-vacuoles. Presently small 

 granules of a yellowish-brown pigment are seen to have been 

 deposited on the surface (fig. 5) of the included masses, and this 

 process continues until the whole is converted into an irregular 

 dark brown mass (fig. 6). Both freshly-ingested corpuscles and 

 pigment may be observed in one and the same cell (figs. 2 & 3). 

 Of the nature of this pigment Kolster says little beyond the 

 statement that it is a htemoglobin derivative, and that some of 

 the granules will give an iron reaction. Such granules are 

 probably similar to the iron-albuminate particles which I have 

 described in the uterus of the Mouse, and which commonly occur 

 in old blood-extra vasates. Bonnet alludes to them as hssmatoidin 

 crystals. 



I myself have not been able to get an iron reaction with these 

 masses in any case. If sections are treated with warm nitric-acid 

 alcohol (by Macallum's method) for 24 hours, and then with acid 

 f errocyanide of potassium, the nuclei of the cells become an intense 

 blue, but the pigment remains unchanged except that it is a 

 little paler. I am, however, able to bring forward a certain 

 amount of evidence as to the nature of the hsemoglobin derivate 

 with which we have here to deal. 



I did not attempt to make a chemical analysis of the pigment, 

 but merely to extract it by different solvents. I proceeded by a 

 twofold raethod : — 



(1) I soaked the foetal cotyledons in water (to get rid of the 

 hsemoglobin in the blood), ground up the tissues in a mortar, 

 filtered, and dried the pigment which had been collected on the 

 paper. This was then dissolved in hot absolute alcohol, and gave 

 a greenish-yellow solvition, which, however, showed no absorption- 

 bands. I failed to get the residue to dissolve in ether or chloro- 

 form (although, as will be seen below. Dr. MacMunn has shown 

 that it will dissolve in these media) or boiling water, although 

 soluble with a greenish colour in 6 per cent, aqueous potash ; 

 in solution in 5 per cent, nitric or sulphuric acid in 90 per cent, 

 alcohol it turned reddish. 



(2) I dried the cotyledons thoroughly, then pulverised in a 

 mortar and dissolved in absolute alcohol. The solution was 

 reddish brown, and, on examination with the spectroscope, showed 

 two dark bands very nearly in the position of the bands of oxy- 

 hpemoglobin. I supposed that these bands were due to the haemo- 



