Henry Gray (1825–1861). Anatomy of the Human Body. 1918.
FIG. 375
 |
| A. Portion of a medium-sized human muscular fiber. Magnified nearly 800 diameters. B. Separated bundles of fibrils, equally magnified. a, a. Larger, and b, b, smaller collections. c. Still smaller. d, d. The smallest which could be detached. |