PENICILLIN TESTS

Timaru Herald, Volume CLVIII, Issue 23323, 5 October 1945, Page 6

PENICILLIN TESTS

White Mice Bred For Experiments Albino Mice are bred by scientific laboratories, where they have a number of uses. Throughout the history of science they have been the subjects of experiments and tests of every kind of vaccine and anti-toxin invented by man to counteract the ravage of disease. They are much the same white, pink-eyed mice that children sometimes have as pets, pets that often die a thousand deaths daily, when the cat pounces on their cage. To-day they are playing an important war role. They are the main subjects of penicillin tests. If mice remain perfectly healthy some time after receiving a penicillin injection it is considered quite safe to release the product for human patients. For there is no reason to suppose that the organs of the lower animals, such as mice, do not function in much the same manner as the human body. The most widely used laboratory mice are the albino "species These white mice are preferred for two reasons; first they breed much better in captivity, and, second, they have a much more prominent vein in their tails, into which penicillin is injected. The mouse is picked up from his cage by the tail when about to receive his free injection. However, he does not relish the operation and wriggles about that much that two persons are required to perform it. One holds him by the tail and neck in front of a piece of glass tubing, jerks him backwards and (Suddenly, lets him go The mouse invariably bounds forward, his body fitting into the glass tubing, leaving only the tail exposed. The tail is then immersed in warm water so is to make the main vein easily discernible. The other injects the desired amount of penicillin into this vein, which carries in into the abdomen.

After serving their purpose the mice are painlessly killed, usually by being dropped into a covered jar containing cotton wool saturated with ether. This makes a continuous supply of fresh mice necessary. So, laboratories have to breed large numbers of them. Timid as a mouse, you have heard people say. And when little albino mice about 12 days old first look at the world through their newly opened eyes they are certainly timid. The slightest movement or sound will send them scurrying under their mother or find them trying to hide in a corner of the cage. And there is certainly more in breeding them than meets the eye. They are extremely susceptible to almost any disease and catch cold easily. In fact, a window left open on a cold night may result in half the colony being wiped out with pneumonia. A colony of 5000 mice, which is not an unusual number, keeps a fair-sized staff busy looking after them. For instance, any animal that dies must be removed as soon as possible. For the carcase is generally half-eaten by other mice if allowed to remain in the cage. This mav cause an outbreak of disease, particularly para-typhoid (form of Intestinal irritation), to which the mouse is extremely vulnerable. Then there is quite a task in feeding them. For a mouse that goes without food for 24 hours is almost starving. Female mice expected to reproduce have their food ration supplemented with greens, usually lettuce leaves. So that food will always be available a dog biscuit is wired to the back of the cage and replaced by another when nibbled away. Tire food ration generally consists of a mixture of mostly rolled oats, a small percentage of powdered skim milk, and cod liver oil, to which a little salt is added. Should this food be left in an open tin the mice will take a special delight in scattering it about the cage, causing it to become contaminated. Or they will use the food tin as a nest and pile in on top 'of each other until the whole cage of them are in -i heap, resembling a round ball of wnice fur This is prevented by the food being placed in a cylindrical tin with sloping wire meshing extending from .he opening, leaving only enough room for tne head of the mouse to enter. If their water is left in an open dish they jump in it and splash it about, getting their fur wet. often catching colds that prove fatal. However. they require little water. A bottle resting on the sloping roof of the cage with a piece of protruding glass tubing drawn to a nipple, and allowing a drip at a time, is sufficient for the mouse, who licks the drip when he feels thirsty. In producing a colony a number of white mice are mated. Then the offsprings are mated with one another and so on. If other than white mice, such as black or black and white, appear in any of the subsequent litters, thev are discarded along with the rest of the lineage. It is not until after about 10 litters, from each succeeding offspring continuing to produce pure white mice, that the breed is considered to be of pure strain and suitable for laboratory use.