The carcasses or parts of carcasses of all rabbits inspected at an official establishment and found at the time of post-mortem inspection, or at any subsequent inspection, to be affected with any of the diseases or conditions named in other sections in this part, shall be disposed of in accordance with the section pertaining to the disease or condition. Owing to the fact that it is impracticable to formulate rules for each specific disease or condition and to designate at just what stage a disease process results in an unwholesome product, the decision as to the disposal of all carcasses, parts, or organs not specifically covered by the regulations, or by instructions of the Administrator issued pursuant thereto, shall be left to the inspector in charge, and if the inspector in charge is in doubt concerning the disposition to be made, specimens from such carcasses shall be forwarded to the laboratory for diagnosis.