agent is also available commercially it is a hydrophilic colloid produced by bacterium of the species xanthomas campestris the colloid is a polymer containing mannose glucose glucuronic acid salts such as potassium glucuronate sodium glucuronate or the like and acetyl radicals other xanthomonas bacteria have been found which produce the hydrophilic gum and any of the xanthan gums and their derivatives can be used in this invention xanthan gum is a high molecular weight linear polysaccharide that is readily soluble in water to form a viscous fluid examplary of the xanthan gums that can be employed is an industrial grade of xanthan gum marketed by the kelco company under the trademark kelzan xc xanthan gum xanthan gum increases the gel strength of the fluid without appreciably increasing its viscosity guar gums and their derivaties can also be used guar gum is a nonionic naturally occurring high molecular weight polysaccharide for example hydroxypropyl guar gum and carboxymethyl hydroxypropyl guar and quaternary ammonium guar gum may be used other suitable viscosifiers and suspension agents can be employed other than those specifically mentioned above and i have found that any one of such viscosifiers and suspension agents or any combination of mixture of suitable viscosifier and suspension agents may be employed including those mentioned above in any amount as may be desired and.