Though the presence of nanotubes in a carbon sample may be clearly detected by electron microscopy, yet it has been difficult to determine if the nanotubes in question belong to a Russian doll or scroll type. This work shows how a chemical reaction with ferric chloride or with potassium metal reveals the differences between the two types of intratube shell arrangement. Scroll nanotubes are intercalated by alien molecules which penetrate from the side of the scroll and fill the intershell spaces. The corresponding intershell spaces expansion was directly observed in this work by TEM. Russian doll nanotubes do not enter the reaction and stay intact. The reaction with scroll nanotubes is accompanied with a remarkable tube swelling which is easily observed by scanning electron microscopy. The presence of intercalated nanotubes may also be detected by X-ray diffraction and Raman spectroscopy.