Re: Who discovered cytoplasm in a cell?

    That is a good question.  We can very easily associate the discovery 
of certain organelles inside of cells to particular people, but it is 
difficult to say 'who' discovered the cytoplasm.  By definition, it is 
essentially what is not an organelle in a cell, the matrix which surrounds 
the other organelles, mitochrondria, endoplasmic reticulum, lysosomes, 
nucleus, etc.  It is in its most basic form what is 'leftover.'
 
     The three people probably most responsible for developing the field 
of cell biology, however, and are credited with discovering several 
organelles in their own right, developed separation and microscopic 
methods which allowed us to take apart cells and look and purify 
individual organelles and compartments, as well as the microscopes 
necesary to peer inside of them.  For their efforts, they were awarded the 
Nobel Prize in 1974.  They were:

Albert Claude, who was born in Belgium, and researched at Rockefeller in 
New York.

Christian de Duve was born in England, and also researched at Rockefeller, 

George E. Palade was born in Romania, researched at Rockefeller, and is 
now at Yale University.

Thanks for the question.
 http://
www.nobel.se/medicine/laureates/1974/press.html

Moderator's Note:
The eukaryotic cell nucleus was discovered and named in 1831 by Robert Brown who
also described "Brownian motion," but it wasn't until 1874 that Rudolf Kölliker
coined the word "cytoplasm."