Remembering the disaster of a disappearing thermometer - Julian Norton

The record temperature I’ve measured was just below 108 degrees. That was in a poorly chicken. Despite the obvious seriousness of the chicken’s condition, I remember saying to the owner, “blimey this chicken is almost roasted”. It did little to alleviate any worry.

Luckily, chickens have a much higher metabolism than mammals and their resting temperature is more than what we’d expect in a sheep, cow, horse, dog or cat, so it was slightly less bad than it might have appeared.

However, I once recorded over 107 in a bullock suffering from pneumonia, which I think is the next highest recording.

Nowadays, it is standard to record the figures in Celsius, so the numbers seem less dramatic. The other big difference is that digital thermometers do not need to be shaken to send the mercury to the bulb at the bottom.

The caricatured image of a vet, screwing up his face with intent whilst vigorously shaking a thermometer is etched on my mind from my early days as a student.

The fact that said vet had a huge nose and looked like a stooped version of Roald Dahl’s BFG made the image even more memorable.

Later, once qualified, I’d do the same sort of thing. It was always better outside, in a field next to a cow who could not stand up. There was less chance of smashing it on a nearby hard surface.

Smartly dressed, a bit like Mr Herriot, in a brown caretaker-style coat, I’d pull my thermometer out of a pocket and remove it from its metal or plastic case. Then, I’d shake it down and insert it into the cow’s rectum.

Often lubrication was added (essential in a cat and dog) but a cow’s rectal can fit in the whole of a vet’s arm

A moment of calm followed as the mercury rose, giving some time to consider the clinical situation. Next, the glass had to be wiped clean and allow the temperature to be read.

I’ve seen some vets wipe the instrument on the rump of the patient (only if it was a cow), but I was taught never to do this by my large animal tutor at university. “It’s demeaning to the cow,” he reprimanded, always sternly. So, in those days, I used the corner of my brown coat, rendering it a subtly different shade of brown over time.

Once the glass was clear, we had to twiddle the tube so that the thin line of mercury was perfectly in line with a magnifying area down the length of the thermometer. This was essential to see anything at all.

Cheaper thermometers had a narrower column of mercury and less powerful magnification, so it could be challenging to read anything.

Modern ones have a battery, a bleep and a digital display so there is no need to shake or wipe and it’s easy to read the number. The modern ones are also very easy to hold onto.

A friend and I once had a disaster at vet school with the one of the old versions whilst taking the temperature of a foal. The youngster objected to our intervention.

I can still recall with horror when the colt contracted his sphincter and the whole four-inch thermometer disappeared inside its rectum.

My colleague had applied too much lubricant and lost his grip. The thermometer was never seen again.