DESCRIPTION OF FIGURES 



All the illustrations have been drawn from pancreas cells of white mice, all 

 except the control showing varying degrees of poisoning with phosphorus, fixed 

 by injection of a mixture of neutral formalin and potassimn bichromate through 

 the blood vessels, according to the instructions given by Cowdry ('16 a). Sec- 

 tions, in thick, were stained with fuchsin and methyl green. In the original 

 preparations the mitochondria are bright crimson, the zjanogen granules purple 

 and the ground substance green. Zeiss apochromatic objective 1.5 mm., com- 

 pensating ocular 6 and camera lucida were used in making the drawings. They 

 were not reduced in reproduction so that they represent a magnification of 1640 

 diameters as they now appear on the plate. 



PLATE 1. 



EXPLANATION OF FIGURES 



1 A portion of an acinus of the pancreas of a normal female white mouse 

 weighing 36 grams illustrated for control. Note particularly the long filament- 

 ous mitochondria with their bleb-like swellings stretching from the basement 

 membrane toward the lumen. The zjoiiogen granules are present, in moderate 

 amount, in the distal parts of the cells. 



2. A group of acinus cells of a female white mouse, weighing 17 grams, which 

 was injected subcutaneously with 0.2 cc. of an 0.0125 per cent solution of phos- 

 phorus in olive oil. Five days later the animal became comatose, and was killed 

 and examined. The cells show very nicely the first stage in phosphorus poison- 

 ing in which a change in the mitochondria is alone noticeable. They have lost 

 their bleb-like swellings and have become shorter and more rounded. Compare 

 with figure 1. 



3 Two acinus cells showing a rather more pronounced change. The mito- 

 chondria are seen in cliimps in the basal parts of the cells, the z>anogen granules 

 are decreased in amount and the nuclei are hard to define. 



4 A single acinus cell, also from the same pancreas, which is of interest be- 

 cause it shows on the left hand side a triangular agglutinated mass of mitochondria 

 and, on the right, such a clmiip which has undergone partial fusion in the process 

 of formation of a lipoid droplet. 



5 Portion of an acinus of a female white mouse weighing 16 grams which was 

 more severely poisoned with phosphorus. It received 0.2 cc. of a 0.05 per cent 

 solutions subcutaneously. On the third day the mouse was comatose. It was 

 killed and examined in the usual way. All the agglutinating mitochondria have, 

 in this stage, fused, and have formed numerous spherical lipoid droplets. These 

 droplets contain clear vacuoles and the cytoplasm surrounding them stains 

 intensely. 



6 A cell from the same pancreas showing a pronounced fatty infiltration as 

 well as the formation of lipoid droplets. 



7 Another cell from the same pancreas showing a great increase in the num- 

 ber of zjTuogen granules. One or two mitochondria may be seen scattered among 

 them. 



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