PLATE i 
The amount of grit recovered from the gizzards of the fowls at the end of the experi 
mental periods: 
1. —Hen killed 
2. —Hen killed 
3. —Hen killed 
4. —Hen killed 
5. —Hen killed 
6. —Hen killed 
7. —Hen killed 
8. —Hen killed 
9. —Hen killed 
10. —Hen killed 
11. —Hen killed 
12. —Hen killed 
13. —Hen killed 
14. —Hen killed 
15. —Hen killed 
16. —Hen killed 
17. —Hen killed 
18. —Hen killed 
19. —Hen killed 
20. —Hen killed 
21. —Hen killed 
22. —Hen killed 
23. —Hen killed 
24. —Hen killed 
25. —Hen killed 
26. —Hen killed 
14th day; weight of gizzard, 13 gm.; weight of grit, 9.50 gm. 
14th day; weight of gizzard, 21 gm.; weight of grit, 13.11 gm. 
21st day; weight of gizzard, 12.01 gm.; weight of grit, 8.31 gm. 
21st day; weight of gizzard, 19.03 gm.; weight of grit, 16.93 gm. 
28th day; weight of gizzard, 13.46 gm.; weight of grit, 11.87 S m * 
28th day; weight of gizzard, 28.19 weight of grit, 22.65 8 m - 
36th day; weight of gizzard, 19 gm.; weight of grit, 16.43 gm. 
36th day; weight of gizzard, 7.10 gm.; weight of grit, 5.03 gm. 
42d day; weight of gizzard, 14.13 gm.; weight of grit, 8.46 gm. 
79th day; weight of gizzard 20.76 gm.; weight of grit, 6.37 gm. 
93d day; weight of gizzard, 15.43 gm.; weight of grit, 11.63 g m - 
120th day; weight of gizzard, 9.63 gm.; weight of grit, 4.96 gm. 
124th day; weight of gizzard, 14.13 gm.; weight of grit, 5.63 gm. 
133d day; weight of gizzard, 7.45 gm.; weight of grit, 4.56 gm. 
143d day; weight of gizzard, 9.86 gm.; weight of grit, 4.75 gm. 
144th day; weight of gizzard, 13.23 gm.; weight of grit, 9.59 gm. 
153d day; weight of gizzard, 11.96 gm.; weight of grit, 6.51 gm. 
154th day; weight of gizzard, 11.76 gm.; weight of grit, 5.96 gm. 
156th day; weight of gizzard 17.36 gm.; weight of grit, 14.03 gm. 
170th day; weight of gizzard, 14.93 gm.; weight of grit, 9.86 gm. 
248th day; weight of gizzard, 4.51 gm.; weight of grit, 2.52 gm. 
270th day; weight of gizzard, 10.46 gm.; weight of grit, 5 gm. 
300th day; weight of gizzard, 10.09 gm.; weight of grit, 3.95 gm. 
330th day; weight of gizzard, 6.53 gm.; weight of grit, 1.93 gm. 
365th day; weight of gizzard, 7.10 gm.; weight of grit, 2.56 gm. 
365th day; weight of gizzard, 9.97 gm.; weight of grit, 5.89 gm. 
(416) 
