"When you are old and gray and full of sleep, and nodding by the fire, take down this book and slowly read, and dream of the soft look your eyes had once, and of their shadows deep"

William Butler Yeats, in his poignant and introspective poem "When You Are Old", checks out the themes of love, time, and the inevitability of aging. The opening lines you provided welcome the reader to review their life from the vantage point of old age, offering a reflective vision of what it means to age.

Yeats begins with the image of being "old and gray and loaded with sleep", recommending a state of weariness and fading vitality. The repetition of "and" highlights the weight of time and its cumulative results on the body and spirit. The phrase "loaded with sleep" can be analyzed both as physical tiredness and as a metaphor for the method of life's golden, meaning a nearly dreamlike state as one nears completion of their journey.

The image of "nodding by the fire" evokes a scene of tranquil domesticity and introspection, suggesting warmth and comfort, yet also a hint of melancholy due to the privacy it implies. It presents the concept of a person surrounded by memories and perhaps regrets as the days unwind.

Yeats then instructs the reader to "take down this book and slowly read", implying that literature, memory, and reflection supply solace and connection through the passage of time. It's an invitation to reconnect with one's past, consequently highlighting the enduring impact of written words and cherished memories.

Finally, he mentions the "soft look your eyes had once, and of their shadows deep", highlighting the tender, ephemeral appeal of youth. The "soft look" indicates innocence and vitality, now transformed by the knowledge, experiences, and possibly sorrows recorded within "shadows deep". These shadows suggest accumulated depth and maturity, portraying how experiences form the soul's landscape gradually.

In general, the excerpt from Yeats's poem is a meditation on life's short-term beauty, urging readers to appreciate the love and experiences of their youth as they look back upon them in their later years. It communicates a bittersweet recognition of love's constancy despite the ruthless march of time, affirming the withstanding power of memory and emotion.