4 
neoplastic disease and the process of inflammation, repair, and 
regeneration, examples of the latter processes are also useful to es¬ 
tablish points of reference. If we prepare the material histologically, 
a set of slides will be returned to the contributor with our diagnosis. 
Specimens are accepted alive, fixed, in blocks, and on slides. 
Frozen specimens are generally unsatisfactory for preparation of good 
histological material, but sometimes are useful when an infectious 
agent must be sought. 
Many specimens arrive poorly fixed for the following reasons: 
1. Delay in fixation - Specimens should be fixed immediately 
after death or when death is imminent since degeneration 
in some cells begins premortem. If a delay is unavoidable, 
specimens should be kept cool in the interim, BUT NOT FROZEN. 
2. Slow or incomplete penetration - To remedy this we recommend: 
a. Always open body cavity or inject fixative; 
b„ Either inject the fixative or preferably, make deep 
transverse incisions intermittently along the length 
of large tumors and organs. This is especially im¬ 
portant for fixatives that penetrate slowly (e.g., 
10 percent formalin); 
c. Use fixatives that penetrate rapidly (Bouin's 
works well for fish, Davidson's for marine 
mollusks, and Dietrich's [FAA] for insects); 
d„ Remove air from the trachae of insects by sub¬ 
jecting them to negative pressure (vacuum chamber) 
while immersed in the fixative for as long as 
bubbles continue to appear; and, 
e. For electron microscopy submit bits of tissue, less 
than 2 mm in diameter, in glutaraldehyde. 
3. Insufficient volume of fixative - A volume of chemical ten 
times the volume of the specimen is recommended. 
REPRINT LIBRARY 
A continuing project to assemble a complete library of reprints 
relating to neoplasms in invertebrates and poikilothermic vertebrate 
animals presently contains more than 2,500 reprints (see computer 
abstract form on next page) is nearing completion. Following final 
editing, searches will be made at a reasonable cost. WE WILL NOT 
HONOR REQUESTS FOR XEROX COPIES OF REPRINTS. 
