Virus-like particles (VLPs) are potential candidates in developing biological containers for packaging therapeutic or biologically active agents.
The Pentagon, the State Department and the C.I.A. have long held that Syria has developed chemical weapons and is also developing biological weapons.
A stronger inspection system is needed, and the administration should work with industry experts to develop one that countries illegally developing biological weapons could not easily evade.
Mr. Bush has also suggested that Iraqi success in developing biological, chemical and nuclear weapons might one day enable Mr. Hussein to hand the weapons over to terrorists.
A pioneer in this field, Professor Denis Noble, co-director of computational physiology at Oxford University, has spent 47 years developing biological models.
Some argue that too much secrecy can actually engender suspicions that the United States is developing biological weapons, prompting other nations to do the same.
