After the verb kram 'to move', when used in the senses of 'continuity', 'energy' and 'development', the ātmanepada is used.,
The word 'kram' governs the succeeding sutras up to 1.3.43 and is understood in them all.
The verb kram by sutra 1.3.78 (after the rest, let the parasmaipada affixes be employed in marking the agent), would have taken the affixes of the parasmaipada; the present aphorism enjoins Atmanepada affixes in certain cases when the verb means to have a taste for &c.
Vritti 'continuity' means unobstructed, or want of interruption (i. e., a taste for, or facility in, anything), sarga 'energy' means application, resolution and determination. Tayana 'development' means increase and growth.
As (1) ऋक्ष्वस्य क्रमते बुद्धिः - 'his reason proceeds unobstructed through the Rig. scriptures i. e., he can easily comprehend the Rig.' (2). व्याकरणाध्ययनाय क्रमते 'the pupil shows energy or exerts to study the grammar.' (3). अस्मिनशास्त्राणि क्रमन्ते 'the shastras are developed in him.'
Why in these senses only? Witness अपक्रामति 'he runs away.',