Title of Davis's paper: "The size of bursa of Yabricius compared with
the ossification of skull and maturity of gonads of some Brazilian
birds".
March 3, 1945
Dr. David 1. Davis, P. A. Sanitarian
Typhus Control Unit, Health Department
San Antonio, Texas
Dear Dr. Davis:
Your undertaking is interesting and important, but I fear too big to be handled
so briefly.
Without experimental controls, Is it possible to classify with accuracy into
immature and mature, especially in small samples colleoted at random seasons?
At least I think you should go into more detail on just how the classifications
were made.
I can't see that Table 1 has any validity. It ignores season, and the proportion
of imatures, of course, vaties seasonally. Are you familiar with the concept of
turnover? If not, the attached reprint might be of help.
Table 2 might be interpreted in terms of turnover, but not knowing the life
history, I can't do it. The samples are too small to be separately significant,
and one can't add them without *adding apples and potatoes".
In general, I just feel helpless in giving you any advice, because I know too little
about the species, and too little about the methods of sampling and classification.
I fear, though, that your materials are too meagre for so comprehensive a treatment.
They undoubtedly could be treated some way, but I can't visualize the way.
Bear in mind that I know no physiology. I would seek the advice of somebody who
knows physiology and who has done such work before going to print: at Wisconsin
Kirpatrick, Irven hass, Dr. R. K. Meyer, Hans P. Thomson would all be more
competent than 1. All but Dr. Meyer are in Service, and he is so busy that I do
not feel at liberty to refer your paper to him.
I appreciate your consulting me, and I assure you I'd like to be more constructive
if I knew how.
Yours sincerely,
Ald. Leopold
Professor of Wildlife Management

cc Meyer, Base Thomeson, Kirpatrick