Kio. 1. Buboutaneoua tissue from thigh of rat which has re- 

 ceived six 2 e. c. intraperitoneal doses of 0.5 

 per cent trypan blue over a period of 6 days. 

 Examined 1 day after last injection. (See 

 protocol Rat 10, p. 7.) Physiological saline. 

 X1C0. 



Fio. 2. Fibroblast and macrophage. Subcutaneous tissue 

 from thigh of rat which has received a daily 

 2 c. c. intraperitoneal doso of 0.5 per cent 

 trypan blue for 4 days. Examined 2 days 

 after the last injection. (See protocol Rat 

 333, p. 8.) Physiological saline. 



Fio. 3. Macrophage. Subcutaneous tissue from thigh of 

 rat which has received four 1 c. c. intra- 

 peritoneal doses of 1 per cent trypan blue over 

 a period of 10 days. Examined 2 days after 

 last injection. (See protocol Rat 31-2, p. 7.) 

 Physiological saline. 



Fio. 4. Fibroblast from same case. Neutral Red 1:10,000. 



Fio. 6. Fibroblast. Subcutaneous tissue from thigh of rat 

 which has received six 2 c. c. intraperitoneal 

 doses over a period of 17 days of a bright red, 

 higfaly diffusible dye (dye H 11) produced by 

 the combination of 1 molecule diehlorbenzidine 

 with 2 molecules beta naphthylamine 3.6 

 disulphonic acid. Examined 3 days after the 

 last injection. Janus green 1:10,000. The 

 dye deposits are pale pink, the mitochondria 

 bright blue-green. 



Fio.fi. Macrophage from samo case. Neutral red 1: 10,000. 



Fio. 7. Fibroblast. Subcutaneous tissue from scrotum of 

 rat which has received 20 daily 1 c. c. intra- 

 peritoneal doses of dye T 1835, the purple 

 dyestuff made by the combination in acid of 1 

 molecule o-tolidine with 2 molecules 1.8 

 amidonaphthol 3.5 disulphonic acid. Ex- 

 amined 20 days after last injection. Neutral 

 red 1 : 10,000. Note the extensive formation 

 of "thread bodies" from the segregation- 

 apparatus. 



Fio. 8. Macrophage from same case. Neutral red 1 : 10,000. 



Fio. 9. Fibroblast. Subcutaneous tissue from scrotum of 

 rat which has received fourteen 2 c. c. intra- 

 peritoneal doses followed by four 4 c. c. doses 

 over a period of 53 days with the blue negative 

 dyestulT (dye II 7), made by the combination 

 of 1 molecule dianisidine with 2 molecules 

 nlpha naphthol 4 monosulphonic acid. Exam- 

 ined 70 days after last injection. Physiological 

 saline. Globular vacuoles, three of notable 

 size, and great numbers of slender threads, 



Fio. 10. Macrophage from same case. Physiological saline. 



In,. 11. Fibroblast, Subcutaneous tissue from thigh of rat 

 which has received two 2 c. c. intraperitoneal 

 doses, followed by two 1 c. c. doses of 1 per 

 cent trypan blue over a period of 10 days. 

 Examined 36 hours after last injection. 

 Physiological saline. 



F.o. 12. Macrophage. Subcutaneous tissue of normal rat 

 Neutral red 1:5,000. 



Fio. 13. Fibroblast. Subcutaneous tissue of normal rat 

 showing the very slight segregation-apparatus 

 characteristic of these cells. The number of 

 these is even somewhat in excess of what is 

 typical. Neutral red 1:5,000. 



Fto, 11. 

 Fio. 15. 



Fio. 10. 

 Fio. 17. 



Fio. 18. 

 Fig. 19. 



EXPLANATIONS OF PLATES. 



The figures represent in each instance actual laboratory drawings of the living cell. The more fugitive structures 

 (e. g., mitochondria) were sketched lirst, the more substantial ones later. In all cases the drawing was carried through 

 to completion in the presence of the material itself. Proportions have been maintained with the camera lucida. 

 \\ In rr not otherwise staled, the magnification is 2,000 diameters; critical illumination with white light, and a Zeiss 

 apochromatic 1.5 mm. oil-immersion lens and XS compensating ocular were used. The position of the nucleus is 

 indicated, but the drawings do not aim to convey information relative to the character or boundaries of the proto- 

 plasm, except as these may be indicated by the deposits of vital dye. 



Mitochondria of macrophage from subcutaneous 

 tissue of normal mouse. Janus green 1:10,000. 



Macrophage. Subcutaneous tissue from abdomen 

 of rat which has received three 4 c. c. intra- 

 peritoneal doses of 0.5 per cent of the bright- 

 red vital dye T 148 (a combination of o-toli- 

 dine with 2 molecules of alphn naphthylamine 

 4.8 disulphonic ncid) over a period of 11 days. 

 Examined 3 days after last injection, .bonis 

 green 1:10,000. Tho vital-dye granules are 

 light pink, tho mitochondria greenish bluo. 



Fibroblast from same case. Janus green 1: 

 10,000. 



Macrophage. Subcutaneous tissue from thigh of 

 rat which has received 10 daily 1 c. c. intra- 

 peritoneal doses of a 0.5 per cent solution of tho 

 deep brownish-red vital-dye 229 produced by 

 the combination of benzidine metadisulphonio 

 acid with 2 molecules beta naphthylamine 

 7 monosulphonic acid. Examined 3 days after 

 last injection. Janus green 1 : 10,000, The 

 dye vacuoles are brownish red, the mitochon- 

 dria blue green. 



Fibroblast from same case. Noutral red 1: 

 10,000. 



Mitochondria of a macrophage. Subcutaneous 

 tissuo from abdomen of rat which has re- 

 ceived 4 c. c. intraperitoneal doses of 0.5 per 

 cent dyo T 148 over a period of 10 days, in- 

 jected every fifth day. Examined 13 days 

 after last injection. Janus green 1:10,000. 

 The dye vacuoles, which were extremely 

 abundant, aro not outlined. 



Macrophage. Subcutaneous tissue from thigh of rat 

 which has received six daily 2 c. c. intraperi- 

 toneal doses of 1 per cent T 148. Examined 1 

 day after last injection. Neutral red 1 : 10.000. 

 This was one of tho most completely engorged 

 macrophages found, though all have one or 

 more vacuoles of great size. 



Fibroblast from same case. Neutral red 1: 

 10,000. 



Macrophage. Subcutaneous tissue from thigh of rat 

 which has received 18 daily 1 c. c. intra- 

 peritoneal doses of 0.5 per cent T 148. Ex- 

 amined 1 day after last injection. (See protocol 

 Rat 18-2, p. 13.) Neutral red 1 : 10,000. 



Fibroblast. Subcutaneous tissue from abdomen of 

 same case. Neutral Red 1:10,000. The pecu- 

 liar deep-red, rodlike crystals of the vital dye 

 are apparent, part of them vacuolar in origin, 

 part intervacuolar. 



Macrophage. Subcutaneous tissue from thigh of rat 

 which has received 7 daily 4.5 c. c. intraperi- 

 toneal doses of 1 pei cent BaumwoUrubio 

 (B.A.S.F.). Examined 4 days after last injec- 

 tion. (See protocol Rat 34, p. 13.) Neu- 

 tral red 1:10.000. It is surprising that the 

 macrophage vacuoles are no larger than those 

 characterizing the fibroblasts. 



Fibroblast. Subcutaneous tissue from thigh of same 

 case. Janus green 1:10,000. Excellent con- 

 trast of tho bright blue-green mitochondria 

 with the pink segregation-apparatus, which In 

 eome few cases shows filar modifications. 



Fio. 20. 



Fio. 21. 

 Fio. 22. 



Fio. 23. 



Fio. 24. 



Fio. 25. 



62 



