If one has made statements, which were true when made, and a material change takes place,1 as a change for the worse in financial condition,2 or impairment in value of a trade-mark,3 or a change in the health of the insured,4 he is guilty of fraud in not disclosing such change where he knows or should know that the other party relies on such original representation. If the purchaser has been shown the actual conditions which exist at the place at which a stream crosses the land which is offered for sale, the vendor is bound to disclose subsequent changes which arise when such stream begins to cut its bank rapidly.5 A similar rule obtains where a false statement was made in good faith but the falsity was discovered before the adversary party acted thereon.6 But a slight change in financial condition need not be communicated,7 nor need change be communicated where it is not known that the adversary party relied on the original statement.8