Cell Specialization

As the 19th century progressed, new methods emerged to fix, slice, and stain tissues and therefore interpret their constituent cells. Especially within medicine, it became clear that cells organize into specialized tissues and organs with varying shapes, playing different roles within a larger organism.

Gradually, with the emerging field of cytology, researchers began to focus on one type of cell or another, exploring in greater detail their structure and function.

Section of illustration of human nerve cells HoverTouch to magnify
Human nerve cells

For example, with nerve cells: Italian microscopist Camillo Golgi and Spaniard Santiago Ramón y Cajal used new staining methods to explore nerve cells and how they group and work together in nervous systems. Although they looked at much the same things, they vehemently disagreed in their interpretations. Where Ramón y Cajal saw separate nerve cells, Golgi saw a single connected mass called a reticulum.

Illustration of section of rabbit hippocampus HoverTouch to magnify
Section of tissue from a rabbit's hippocampus
MBLRare Books Collection
Illustration of human cerebellum nerve cells, stringy or spidery masses with a central focal point HoverTouch to magnify
Human cerebellum nerve cells
MBLRare Books Collection

They shared a Nobel Prize but still disagreed. Each pointed to his particular images as evidence for his claims. Their innovations, observations, images, and arguments show how exciting this time in history was. And how difficult it can be to interpret what we see with microscopes.

While these researchers were busy observing and interpreting specialized cells, others were asking: how do complex organisms with specialized types of cells arise from single germ cells?