Which individual was known as a microscopist for the U.S. Department of Agriculture?

The individual recognized as a microscopist for the U.S. Department of Agriculture is Dr. Johannes Purkinje. He made significant contributions to the field of microscopy, particularly in his studies of plant and animal tissues. His expertise in utilizing microscopes allowed him to advance the understanding of biological structures, which was valuable for agricultural research and practices.

Dr. Purkinje's work laid the foundation for many techniques used in modern microscopy and helped to improve the methods of studying crops and other agricultural subjects. His contributions went beyond just microscopy; he also had a profound impact on biology and physiology, which indirectly influenced agricultural sciences.

In contrast, while the other individuals listed contributed to various fields, they did not specifically gain recognition for their work with microscopy within the context of the U.S. Department of Agriculture. For instance, Thomas Bewick was known for his work in wood engraving and natural history, Thomas Taylor was an influential figure in Scottish history and philosophy, and Sir William James Herschel is noted for his contributions to fingerprinting, but he was not directly associated with the role of a microscopist in the context given.