424 University rarm Pl.ae 
Diiso      ofWldlife Maaaet                             Otbr20, 13 
Dr. L.S. Fnamer 
Dpartent of Biochemitry 
University of Minnesota 
St. Paul, Mneota 
Dear Dr. Palmeri 
Dr3. N. Chapman 5RYe - your nan   in  esponso to v 
inquiry as to wer I could got adoce as to the ffeot of foos oa 
rrproutive pow and popuation irni. of rodents. 
On western rfng ladsI heavy' rodent poi~uations oeo. to 
be asooiate& in *oe my      with ov  asd r.nes. At the No 
Mexcoo W4iultural Collog   I homrd a theory that mt rae grasses 
are deficient in phshou     Irt that phoporus is mor .Wandeat in 
the woodit which spring up wheove-gamn thin. out the rv.ge grss. 
The theory Is that abuzuaneo of phopor'us farnIshe4 by weoe 
stimlates reproduction and hence raises populations. W cheistry 
is insuffioient to chok either the allog    di-fferential betwee 
gmse and wess .r the alqe& effeot on rodent 1w1s. Is there 
wtisg In ymir experienc whih woau enable you to sed ligt on 
this or aW similar theory of rodent popuatiosT? 
Dr. C        told me that ym had worked only with laboratory 
rodents, but I imgine n on. has dn    e      work with wld speies 
to knw any'thing abut th. 
Sincerely you"S 
Aldo Leopold 
Professor of Wildlife U~nmeat 
cc Chapman 
Holt