After completing the puraka, both the nostrils should be closed, the right one with the thumb, and the left one with the last two fingers. The head should be lowered down in the front, and the chin set against the jugular notch below the throat. This technique is known as "jalandhara-bandha." It should beaccom"panied by two other bandhas called respectively "mulabandha". and "uddiyana-bandha". The former involves contraction of the anus, the latter, contraction of the pelvis (lower abdomen). These three bandhas are supposed to have a special significance. After holding the breath for ten seconds after the putaka through the left nostril, the head may be taken to its normal erect position, the muscles of the anus and pelvis are relased, and then rechaka and the next puraka are made through the right nostril. Another kumbhaka is then made, which is followed by rechaka through the left nostril. The number of rounds involving kwnbhakas may be increased by two per week,so that within five to six weeks all the ten rounds would include holding of breath. After practising twenty kumbhakas (of ten seconds duration each) every day for about a month, the duration of each kumbhaka may be slowly increased to fifteen seconds.This would be achieved in about a month and a half, and may be practised regularly for nearly a month. Then the time may be progressively increased to twenty seconds.Another sitting may be added at this stage. In the beginning the dose of ten rounds (i.e. twenty kumbhakas of twenty seconds each) may be split up into two doing ten kumbhakas in the morning and ten in the evening. The number at both sittings may be increased by one every week, so that after five weeks one will be doing forty klllnbhakas per day, twenty in the morning and twenty in the evening. The maximum dose of kumbhaka that an advanced student of yoga is expected to practise every day, as mentioned in Hathayoga-Pradipika , is eighty kumbhakas per sitting, with four sittings in a day. One should thus practise Pranayama in the morning, evening, and at midday and midnight. The maximum duration of kwnbhaka in each round is traditionally expected to be sixty four matras. The definition of a matra seems to vary in different traditional texts. For example, in the Yogatatvopanishad it is said that a matras is the period required for taking the hand round the knee neither hastily nor slowly, and making a sound by sliding the middle finger downward from the apex of the thumb. This means nearly thirty six matras in one minute. A matra is defined in the Markandeya Purana as the time required for winking of the eyelids, or for uttering a syllable. This may mean about one hundred matras per minute. The Brihadyogi-yajnyavalkya Smriti speaks of a matra as the time required for making a sound thrice by the middle finger and thumb, or for moving the hand once around the knee and the thigh. This is rather vague. Brahma. nanda, the commentator of Hathayoga-Pradipika mentions several meanings of the word "matra".We need not go into the details of these meanings.It seems reasonable to assume that sixty four matras are equal to nearly forty eight seconds.A kwnbhaka of this duration may be described as of the "highest type". A duration of twent four seconds would make a kumbhaka of the "medium type", while a kwnbhaka lasting only twelve seconds may be called the one of a "low type". It is supposed that a kwnbhaka of the low type causes profuse perspiration of the body, the one of a "medium type," cause tremors in the body, while that of the "highest" type may cause the body to be raised from the ground. The highest type of kwnbhaka must however, be developed with due care and caution: preferably under the guidance of a person .who has himself mastered it. The author of the Hathayoga-Pradipika (II, 15-16) does well to warn the student of yoga against the ill effects of an improper practice or Pranayama. He has rightly compare breath control with the process of taming a lion or an elephant, emphasizing the need for exercising caution and care.