Can spirits take on different forms?

Can a spirit after leaving the form take cognisance of material forms any farther than what is seen by the medium?

A spirit that has passed through the chemical change called death perceives the external of all physical forms through the electromagnetic aura that emanates from the external forms that have an earthly existence, for instance, when I am apart from this physical body, this medium, should I wish to see any object in this room, I would first seek to come within the atmosphere―or magnetic sphere of this medium―or some other that might be in this locality. When the scientific man desires to gain a clear understanding of the heavens, he takes his glass that he may come into rapport with the heavenly bodies through the peculiar power of the glass. The spirit uses the medium―or the magnetic life that passes from these mediums on precisely the same conditions by which they may come into rapport with these external forms. There are heavenly bodies so far distant from your external vision that you cannot without some extra aid see, but if you could obtain the necessary extra aid, you could see them. So, with regard to these objects. We can see them―we can feel them. We can smell the aroma of your flowers by coming into rapport with them, but in our proper spiritual state, we see only the spiritual part of these flowers.

―Spirit Father Henry Fitz