It is springtime, and soon I will expand and open up to see the bright face of the sun. Sunlight is a source of my food and the service I do. The more sunrays that hit my surface, the faster I grow, and will generate a great need of life on Earth: oxygen. To the unappreciative eye, I am just a leaf, but the complexity of my reactions are still a great puzzle to scientists who work in large institutions trying to understand the processes going on inside me. It takes them many years to fully comprehend a single step in the process of oxygen generation that takes place within me.

Although I am very simple, thin, and fragile, I have been charged with a great service. During the entire summer, I endure the heat of the sun without drying up or wilting. This is because I am constantly fed with a flow of water and minerals from my branch, which was soaked up from the tree’s roots embedded deep in the Earth. This constant flow of water enables me to keep upright, sturdy, and open. Most of the water is evaporated through my thin surface, but a small part of it is broken up to provide you with the oxygen that you need to survive. Although this sounds very simple, it requires a great deal of energy. This energy is provided to me through the sun and the sugars that are made in me during this process.

When no water falls from the clouds, I suffer. I cannot keep upright to provide you with the oxygen that you need. When it is too hot and there is no rain, I suffer again. Were it not for the babies, the old, and the weak among you, I would dry out completely. When human beings oppress each other, I suffer, because under these conditions water does not fall to Earth despite the clouds in the sky. These clouds also block the sunshine that I need to serve you with oxygen.

Right now it is autumn in many places and although I did not dry up in the hot months of the summer, I am now ordered to wither and fall. My color changes from green to yellow, orange, red, and finally brown. As I drop to the ground, people step on me. I get crushed and grinded to pieces as I return back to Earth. The matter used to create me mixes with the soil, until next spring, when I will be high up on the branch looking at you one more time, reminding you of a new beginning after death.

We are three pairs of large glands that secrete into the mouth through canals and hundreds of very small glands around the throat. The large glands in front of the ear area are called the parotid glands, the glands under the chin are called the submandibular glands, and the ones under the tongue are called the sublingual glands. The parotid glands secrete saliva from the sides of the upper molar teeth, the submandibular glands from the front under the tongue, and the sublingual glands from many openings in the mouth’s base. There are also many more salivary glands in your inner cheeks and lips, and in all other wet spots in your mouth and throat.

Every sugary and starchy food you eat must first interact with our secretion in order to be digested. For this, an enzyme called ptyalin has been placed within us. But for this enzyme to work properly you must chew your food well. Also, you shouldn’t eat anything that is too hot or too cold, or anything that could change the pH (acidity) level of your mouth. Otherwise, this enzyme cannot function correctly. We produce an average of about 1000 milliliters (one liter) of secretion every day; however, we have the capacity to produce 1.5 liters of saliva per day.

Sometimes, the calcium in our enzymes may precipitate and form tartar due to acidic foods. Tartar can sometimes block our secretion canals. When you eat something, saliva production accelerates; but if our secretion canals are blocked by tartar, then the saliva cannot flow. This causes infection accompanied by severe pain and swelling. If our canals aren’t completely blocked, we may swell a little while eating, but we will slowly deflate after a while. Microbes can reproduce easier in accumulated saliva that cannot flow, thus causing severe pain and swelling. Our most frequently seen infection is the one that makes the parotid glands swell up, and is called the “mumps”. Even though it is seen more frequently in children, it may also be observed in adults. The swelling of both of the parotid glands is more frequent in alcoholics.

The thiocyanate ions that have been put in our saliva secretion kill the bacteria in your mouth by breaking them apart. In addition, lysozyme enzymes attack and kill bacteria in your mouth while digesting food remains to prevent the bacteria to feed and reproduce. Hungry bacteria perish more easily. Our infinitely merciful Lord put special proteins called anticorps in our saliva to prevent many diseases that can enter from the mouth before they develop. These anticorps act like special agents that attack and destroy bacteria. If we don’t secrete enough saliva, ulcers will develop in your mouth frequently. If they last long enough, they will get infected and also cause tooth decay.

The control of our secretion is connected to an area that includes the appetite center in the brain stem through the involuntary nervous system. When you smell or taste foods you like, we immediately start secreting saliva as a reflex. When you come across foods that you don’t like, or when you get scared or excited, we slow down saliva production, again reflexively. Suspects in the past used to be given a handful of rice to swallow, with the thought that the real culprit would not be able to swallow them, because the excitement caused by the feeling of guilt would cause his/her mouth to dry.

Diabetes, which is a systemic illness, also has a negative effect on our functioning. Diabetes presents itself with drying of the mouth, along with excessive intake of water, and the frequent need to visit the restroom. One type of rheumatoid arthritis may also cause dry mouth and dry eyes together with joint pain.

As you see, Peter, I’ve briefly explained to you how invaluable and necessary your saliva is. I have not even mentioned our histological and anatomical structure, which resembles a bunch of grapes. I believe you can imagine how each and every one of my gland cells is like a perfect biochemical factory. You wouldn’t relate all these to your mouth being wet for no reason, would you?

Irfan Yilmaz is a professor of biology in Dokuz Eylul University, Izmir, Turkey.

I imagined you travelling on the hills of my heart.

A mirage, I know, but it sufficed to calm the anguish of my heart.

As I mentioned you again, nothing else remained in my memory.

I wish I could move the whole of time with love of you,

and travel in your horizons, rising high like spirits;

I wish I, finding a way, could fly into your heart.

I wish I could move the whole of time with love of you.

I’ve come to understand that it’s too late to reach you,

I will lament continually for the pangs of separation;

Lamenting, I will wait with ever-fresh hopes of union with you.

I’ve come to understand that it’s too late to reach you.

My heart, like a pigeon’s, trembles following your footprints;

I beg you to give me a feather from your wing,

so that I might continue after you and reach you.

My heart, like a pigeon’s, trembles following your footprints.

O Rose, which changed dry deserts into gardens of Eden,

Come and, with your intoxicating colour, enter my heart!

It’s time that you smiled into my weeping eyes,

O Rose, which changed dry deserts into gardens of Eden!

Let me be your slave who, like Majnun, runs after you,

Spark such embers within me that I catch fire like a furnace,

and come out of this dream, enduringly bitter without you.

Let me be your slave who, like Majnun, runs after you.

I count how many days have passed without you,

and a gloom invades my soul, darkening it;

Let me see your face, as the sun is about to set.

I count how many days have passed without you.

Let my setting, the last moment of my life, be a new rising,

and my heart be invaded by the colours of your climate;

let lutes be played everywhere, and reed flutes heard.

Let my setting, the last moment of my life, be a new rising.

***