[R] How to assign text string as object?

[Ing. Michal Kneifl, Ph.D.]

I have a problem I cannot get over for a long time. Imagine I have a  
data frame with 17 colums. 16 of them are craniometric variables of  
Cervus elaphus and one contains age.
The data frame has 83 rows.
I want to write a loop which plots the values of each craniometric  
variable against the age. The names of columns are V1, V2, V3, etc...
What I have done till now was writing this:

layout(matrix(1:16,4,4))
plot(V1~AGE)
plot(V2~AGE)
.
.
.
.
etc.
How to assign a string in the loop so that the program understands it  
is an object?
Thank for your help in advance.

Michael