1890-91.] AMPHIBIA BLOOD STUDIES. 259 



chiefly in the higher types of animal Hfe, the analogies between chloro- 

 phyll and haematin and the derivation of the digestive ferments from 

 chromatin. 



These and other related subjects I intend to discuss in a future publication. 



EXPLANATION OF FIGURES. 



Figs. 1-4 are drawn from preparations from the adult Neciurus^ and Figs. 5-7 are 

 taken from larval AmblystoDiata (A. picnctatum). 



Fig. I. Red disc from a cover-glass preparation of the blood. Corrosive sublimate, 

 Indigo-carmine Fluid — X700. 



Fig. 2. Red disc from splenic vein. Chromic acid, Indigo-carmine Fluid — X700. 



Fig. 3. Red disc, cover-glass preparation. Chromic acid, Haematoxylin, Eosin — X 

 700. 



Fig. 4. Red disc cover preparation. Corrosive subUmate, Haematoxylin, Eosin — X 7oo. 



Fig. 5. Red disc from heart cavity. Flemming's Fluid, Haematoxylin, Eosin — X 1,000. 



Fig. 6. Red disc from gill vessel. Osmic acid, Haematoxylin, Eosin — Xi,ooo. 



Fig. 7. Cover-glass preparation of red blood cells. Fresh, acetic methyl-green — X 

 1 ,000. 



Fig. 8. Group of blood cells from a vascular sinus in a section of the spleen of 

 Necturus. In the centre is represented a haematoblast in mitosis and vn'Csx its chro- 

 matin so changed chemically that it takes the sulphindigotate portion of the reagent ; 

 a^ a red disc, b a leucocyte. Chromic acid, Indigo-carmine Fluid — X700. 



Fig. 9. From a free swimming At)iblystoma larva. 



a, Haematoblast from the concave side of one of the aortic arches, in division and 

 showing in the abundant chromatin as well as in the cytoplasma a slate or slate-brown 

 reaction. 



b, an endothelial cell from same aortic arch in same preparation undergoing mitosis 

 and showing the normal reaction of the staining fluid. 



Flemming's Fluid, Haematoxylin — Xiooo. 



Fig. 10. Haematoblast from concave side of aortic arch in a free-swimming larval 

 Amblystotna. Flemming's Fluid, Hsematoxylin, Eosin — X 1,000. 



Fig. II. Haematoblast from same preparation as last — X 1,000. 



Fig. 12. A dividing haematoblast in the last stage of its development, showing two 

 kinds of chromatin in the nuclear figures. Cover-glass preparation. Corrosive subli- 

 mate, Haematoxylin, Eosin — X 1,000. 



Figs. 13-14. Haematoblasts in the last stage of their development, showing a de- 

 generated chromatin between the regular chromatin loops of the dividing nuclei. 

 From the heart cavity of a free swimming Amblystotna larva. Flemming's Fluid, 

 Haematoxylin, Eosin — Xi,ooo. 



