Werwolves - the goods

Of course, everyone is wondering, how does one become a werwolf? (Besides hereditary misfortune and a certain bite.) Look no further:

"The locality chosen, our candidate must next select a night when the moon is new and strong. He must then choose a perfectly level piece of ground, and on it, at midnight, he must mark, either with chalk or string--it really does not matter which--a circle of not less than seven feet in radius, and within this, and from the same centre, another circle of three feet in radius. Then, in the centre of this inner circle he must kindle a fire, and over the fire place an iron tripod containing an iron vessel of water. As soon as the water begins to boil the would-be lycanthropist must throw into it handfuls of any three of the following substances: Asafoetida, parsley, opium, hemlock, henbane, saffron, aloe, poppy-seed and solanum; repeating as he does so these words:--

"Spirits from the deep
Who never sleep,
Be kind to me.

"Spirits from the grave
Without a soul to save,
Be kind to me.

"Spirits of the trees
That grow upon the leas,
Be kind to me.

"Spirits of the air,
Foul and black, not fair,
Be kind to me.

"Water spirits hateful,
To ships and bathers fateful,
Be kind to me.

"Spirits of earthbound dead
That glide with noiseless tread,
Be kind to me.

"Spirits of heat and fire,
Destructive in your ire,
Be kind to me.

"Spirits of cold and ice,
Patrons of crime and vice,
Be kind to me.

"Wolves, vampires, satyrs, ghosts!
Elect of all the devilish hosts!
I pray you send hither,
Send hither, send hither,
The great grey shape that makes men shiver!
Shiver, shiver, shiver!
Come! Come! Come!"

The supplicant then takes off his vest and shirt and smears his body with the fat of some newly killed animal (preferably a cat), mixed with aniseed, camphor, and opium. Then he binds round his loins a girdle made of wolf's-skin, and kneeling down within the circumference of the first circle, waits for the advent of the Unknown. When the fire burns blue and quickly dies out, the Unknown is about to manifest itself; if it does not then actually appear it will make its presence felt."

- Werwolves by Elliott O'Donnell

Sadly I will never know if this ritual works, because right off the bat I'm not sure I can find opium, and I'd rather not 'freshly kill' a cat. I still find it peculiar that there is no explanation as to why a person might be "desirous of acquiring the property of lycanthropy." It does seem unusual that it is totally conceivable for a person to find all these items, and cast this spell. Yet, we should presume it wouldn't work? There is another stipulation early on:

"(The desirous person) should be in earnest and a believer in those superphysical powers whose favour he is about to ask.

Assuming we have such an individual he must, first of all, betake himself to a spot remote from the haunts of men. The powers to be petitioned are not to be found promiscuously--anywhere. They favour only such waste and solitary places as the deserts, woods, and mountain-tops."

I suppose if the ritual did not work, one could think that they had not believed hard enough, or hadn't chosen the right location. How many people are this "desirous" of becoming a monster anyway?
Postscript - for the curious, asafoetida.