Frederick D. Gardner, a young fruit dealer in Middletown, Conn., left that place on July 28 for this city to collect bills and make purchases for his establishment. Mr. Gardner spent several days in reaching the city, as he stopped at many small places on his way to collect small bills owed to him. Arriving in New-York he went to stay at the Bancroft House, making purchasing tours each day. Last Wednesday morning he went out as usual, and from the time he left the hotel none of his friends know what has become of him. His disappearance is as complete as it is mysterious. He had only about $150 with him at the time he went out, and it is known that he did not obtain any more money. His accounts are all straight. Everything he bought he paid for in checks, which have all been fully met, and his books at Middletown, having been carefully examined, are found to be correct. He has a wife, who lives in Middletown, and who, with her father-in-law, Ira Gardner, a Middletown merchant, is anxiously looking for her husband.