It may be that some alchemists performed animal sacrifice in order to raise the vibration or state of the animal's prima materia to a higher state.

So then, I assume you are opposed to doing the same to plant or mineral substances?

However my own experience has taught me that it is unnecessary to harm another in order to attain my own heightened state and I can't help but think that most adepts would feel the same way.

I think it is futile to guess how most adepts would feel, because the fact is that very few occultists or alchemists have ever met one and their preconceptions are based solely on erroneous accounts in popular books.

So it is not a question of whether it is possible that these actions were potentially "holy" in nature, but rather that even if there were a completely pure intention, you nevertheless must create suffering in another in order to perform such a rite

Who said anything about a rite? Alchemy is not an Anne Rice novel. It is a divine science, not superstition.

I recognize that this may be a modern take, but it seems to me that an adept would cultivate and express compassion as a result of following the path, not use it as a "license to kill," by reducing everything to either "perfected materia" or "imperfected materia."

Compassion may take forms that you do not understand. The Great Alchemist - God - inflicts death upon every living creature on the planet. Do you see this as morally wrong? Or is it possible that there is a purpose that you do not presently understand?

Form is also sacred, as is self-sovereignty.

Then I suppose you do not eat meat? Or plant matter?

Life consumes itself in order to live.

To me the rationale you have just espoused is a slippery slope to solipsism and lack of compassion.

You have not understood what I have said.

My experience has also taught me that most of the time, the animals and ingredients are symbolic code language for an inner aspect of man, not actual animals.

This is a modern, popular view of alchemy and it is not supported by the writings of the alchemists themselves. We work not only with the inner mechanisms of man but his outer mechanisms as well.

"As above, so below". Not "As above, sometimes so below". The outer and the inner are One Thing. While the animals and the ingredients are (usually) symbolic, the believe that they refer in most cases to the inner aspect of man, while a "reasonable" deduction, is incorrect. The reality is that a small minority of the old alchemical texts referred to inner realities, this being in most cases transmitted from Adept (or Master) to his "Philosophical Son".

By transmission btw, I do not mean an intellectual teaching.

So I am wary of any alchemist who would espouse the literal killing of an animal on the grounds that it is possible that this person in earnest pursuit of enlightenment has misunderstood the basic tenets of alchemical literature.

There key difficulty here being that you do not have an accurate understanding the basic tenets of alchemical literature. This is not meant as a slight but rather a recognition that very few do.