Teasing “Books on Practical Magic Vol. I” p.73-74 translated from German
Magical Breathing Exercise
The foremost necessary "internal aid" is the proper "readiness" of the magician. We'll explain this "readiness" with its individual components again in the work schedule:
The preparedness of awakened internal forces for energetic action;
The necessary "Agent" (driving and shaping force), called "Prana" or "Od", in sufficient quantity;
The prior purification, dissolution, alignment (harmony, tranquility, self-assurance, patience, absolute will).
Here comes a second pure exercise of imagination, that every interested reader ideally wants to learn, improve daily, and intensify:
Through the four types of breathing, listed under "Main Breathing Rules", we charge ourselves strongly with Odic force, consciously and vividly imagining taking in a particularly large amount of Od this time. We store all Odic force in the brain, in the crown region.
Now the new exercise commences. Like from an atomizer, a whitish substance now emanates from the crown point of our head - we visualize it mentally - falling evenly to all sides of the body like a fountain, covering it down to the feet with a "protective shield", a casing that allows only the desired forces to pass through, while blocking harmful or disruptive radiations.
The day will come, that'll see foreign forces shatter on the protective casing - that's how strong, solid, secure, indestructible, and "actual" it has to be. The inner senses, awakened by then, will see, feel, and utilize it.
This process is a magical one with all the characteristics of such. Anyone who has the necessary confidence and certainty in the "generation" of the protective shield, who truly feels it's "there", who senses how the protective barrier forms, how the Od is flowing from the head down in all directions, shielding the body from all sides: upon successfully accomplishing this task they are skilled in magical work and protected against any potential "mishaps". Nothing can happen to them as long as the armor holds and is maintained.
The reader, who's developed their power of imagination and manifestation to such an extent that they "know" of said protection - especially if they forgot to develop it and "noticed" its absence - can now proceed. They'll succeed perhaps in everything, and maybe beyond what is described in the following pages!
The student has become the Magus.