HUSBANDRY, EQUIPMENT, AND PROCUREMENT OF MICE 543 



and then into mouse rooms. The lowest air pressure should be maintained in the 

 equipment disassembly and washing machine, feed-in area. In this way air will flow 

 out of a mouse room when the exit doors of a room containing dirty equipment are 

 opened and down the corridors used solely for transport of such materials. In a sit- 

 uation requiring containment during an experiment with a transmissible agent, some 

 modification of this pattern must be made, depending on the particular problem being 

 investigated. 



Experimental rooms should be only large enough for use by a single principal 

 investigator. If it is found necessary to have more investigators use a single room, 

 one should be reponsible for supervision of the room. This procedure provides proper 

 liaison among several investigators and animal husbandmen. In this way proper 

 control of caretaking and procedures for control of diseases can be maintained. 



The humidity requirements of mice are not well known. Practical experience 

 indicates that a relative humidity of 30 to 50 per cent is most satisfactory. The 

 reasons for suggesting this range are not scientific and are derived mainly from standards 

 of human comfort. In an extremely dry atmosphere certain types of dermatoses are 

 more prevalent in mice, although again the correlation is purely empiric. 



General care and handling. 247, 1410 — Mice are as much creatures of habit as are 

 larger animals or poultry and are as easily upset by abrupt changes in routine or un- 

 usual noises. Routines of changing cages and general caretaking should be established 

 and strictly adhered to. Cages, water bottles, and equipment coming in direct contact 

 with mice should be replaced weekly with sanitized or sterilized replacements. Such 

 materials should have foreign material removed before being washed. The washing 

 process should follow a general routine of prewashing or soaking, washing with soap 

 or detergent, and one or more rinses with fresh water of 180° F., in the order men- 

 tioned. Disinfectants or germicidal agents are not necessary if the detergent completely 

 removes all material from smooth surfaces and if this is followed by a thorough rinsing 

 at 180°+ F. 



Mice should be handled (figure 87) only by long forceps (except for experimental 

 procedures). These are used by grasping the mouse firmly but gently by the base 

 of the tail. Two or more pairs of forceps should be available, to allow the unused 

 pairs to soak in a solution of disinfectant between use. A single pair should be used for 

 handling only those mice in a common unit and a fresh, disinfected forceps used for the 

 next group. The liquid disinfectant should completely immerse the lower 3 to 4 

 inches of the forceps and should be of a type which is neither irritating nor carcinogenic. 

 A commonly used preparation is 0.5 per cent Wescodyne solution,! although many 

 similar products containing bound iodine are available. 



Experimental procedures should be conducted in a closely adjoinig area, and only 

 the necessary cages of mice removed to that area. The experimental work should not 

 be done in the aisles between cages unless it is minimal, such as visual observation, 

 counting of newborn mice, and the like. Surfaces for experimental and other types 



t West Chemical Products, Inc., 40 West Street, Long Island City, N.Y. 



