The Mukhya Upaniṣads

Aitareya · Adhyāya 1 · Khaṇḍa 3 · The Search for Food, and the Discovery of Who Asks

Passage 7

तत्त्वचाजिघृक्षत्तन्नाशक्नोत्त्वचा ग्रहीतुं स यद्धैनत्त्वचाग्रहैष्यत्स्पृष्ट्वा हैवान्नमत्रप्स्यत् ॥ ७ ॥

In plain words

He tried to seize it with the skin; he was unable to grasp it with the skin. Had he grasped it with the skin, i.e. merely by touching it, then merely by with the skin, i.e. merely by touching it, one would have been satisfied by food.