Organs deteriorate if you do not use them properly, just in the same manner as hands and legs get atrophied by disuse, and are developed by muscular exercises, etc. There is intimate connection between sight and memory, and also hearing and memory. He who has an acute sight, a keen perception, a good power of observation and hearing, will have very good memory. There are counterparts of these external parts in the internal astral body. They are called astral senses. A Yogi hears through astral ears, and sees through astral eyes, and thus develops clairvoyance and clairaudience. He can hear sounds from distant lands, and see objects that are in distant localities.
Generally, people are very careless. They have no interest to learn higher things and to have a fund of knowledge. There are millions of people in India who cannot sign even their names. India, the land of Rishis and sages, still abounds in ignorance when compared with America and the Continent. Even a small boy, who brushes a pair of boots and applies polish in the streets of London and Paris, knows politics, reads newspapers, and can discuss things nicely. The masses of India are steeped in ignorance and darkness. The root cause is carelessness, indifference and cold apathy.
To get success in life, to become an able doctor or a lawyer or a good successful businessman, the ears and the eyes should be developed to an enormous extent. A blind man, or a deaf and dumb man, is practically a living dead man. All wealth and knowledge comes from the ears, the eyes and the organ of speech. These Indriyas are the Ayatana, or the receptacles, for riches and knowledge. The knowledge of the sense-universe comes through these two channels and is expressed by speech to others. Whenever you move about, you should be very alert. You must keep the eyes and ears sharp. You should try to remember all things and news that you have seen, heard or read. You should develop the power of observation. Be very attentive. Attention helps observation. Bring the power of curiosity into play. Curiosity will turn into desire after sometime. Interest and attention will come in automatically. Whenever a man talks to you, give him a very patient hearing. If there are useful and interesting points, note down in your pocket-diary then and there. Go through the pages of the diary once a week.
Exercises for Developing Hearing
Keep a watch very close to the ear, and hear the sound attentively. On the second day, keep it at a little distance, and hear the 'tick, tick' sound. Everyday increase the distance, and train yourself to hear the sound. Plug the ear with the index-finger of your hand. Train the ears alternately.
There is also another exercise. Close both the ears through Yonimudra with your two thumbs and try to hear the Anahata sounds that emanate from the heart-lotus. You will hear ten varieties of sounds, such as, the sound of a flute, Mridanga, Veena, conch, bells, thunder, humming of the bee, drum, etc. Allow the organ of hearing (ear) to shift from one sound to another and carefully differentiate the various sounds, and eventually fix the ear on one sound. First try to hear the gross sounds and then the subtle sounds.
There is also a third exercise. Fix the ears on the Pranava Dhvani that emanates from the Ganga. It will be heard like "Bhum", or long "OM." Train your ears to hear this sound. Do this exercise in the morning at 4 a.m. or at night at 9 p.m., when the din and bustle of the town is at an end.
Keep your ears keen. Try to differentiate the sounds of various kinds of birds, beasts, children, factories, motor-cars, aeroplanes, cycles, shrieks, yells, snores, sobbing, crying, laughing, mocking, joking, etc. It is advisable to sit in a quite room. Close your eyes and try to concentrate on these sounds. Distinguish them. You must be able to find out, from hearing a voice of a person at a distance from within your room, that such and such a man has come in front of your room. There are some people whose voices have some resemblance. You should be able to find out that the voice of Mr. Bose more or less resembles the voice of your cousin Mr. Ganga Prasad. You should be able to find out the nature of Ragas and Raginis from the nature of vibrations and undulations, such as Kalyani, Todi, Bhairavi, Kanada, Kamboji, Deepak, Durbari, Malkose, etc. Try to hear the sounds of the heart by applying your ear to the chest of another man. You will hear the sounds "lub-dhub." Pay heed to the sounds of sparrows and other birds, and try to differentiate their sounds. Sometimes they sing. At other times, they give signals of alarm to invite their mates and friends when there is impending danger. Animals and birds have got their own languages. Yogins can understand their languages. There is a particular technique in Samyama (or the practice of Dharana, Dhyana and Samadhi) on sounds. Some males have the voice of females, and some females the voice of males. You must be able to differentiate. You must be able to know the hissing sound of a cobra, its nature, strength of vibration, etc. Even at a distance you can say, "There is a cobra in that room." Cats express peculiar sounds during, before and after copulation. Dogs, horses and elephants are very intelligent animals. They have got simple consciousness. They laugh and smile and express their feelings of joy and gratitude by certain sounds. You must be able to understand the nature of the sounds. By the practices enumerated above and careful observation, you will be able to develop a wonderful power of hearing. You can get on well in your business ventures and vocations in life. Sharp ears and keen sight bring more wealth.