
The Development of a Simple Nervous System
Tracing the pedigree of nerve cells in the embryonic growth of dwarf and giant leeches yields preliminary clues to the functioning of the adult nervous system

The Development of a Simple Nervous System
Tracing the pedigree of nerve cells in the embryonic growth of dwarf and giant leeches yields preliminary clues to the functioning of the adult nervous system

Prematurity and Uniqueness in Scientific Discovery
A molecular geneticist reflects on two general historical questions: (1) What does it mean to say a discovery is "ahead of its time"? (2) Are scientific creations any less unique than artistic creations?

Cellular Communication
Cells communicate by means of hormones and nerve fibers. Such communication and all other forms of communication are founded on the information incorporated in the molecules of nucleic acid

The Multiplication of Bacterial Viruses
The organisms that infect bacteria provide a means of studying the mechanism of heredity. Some new tracer experiments reveal that their reproduction has several rather unexpected features