big ints in mongodb?

ruby-1.8.7-p334 :022 > col.update({:_id => id}, {:test => 0})
 => 105 
ruby-1.8.7-p334 :023 > col.update({:_id => id}, {"$inc" => {:test => 7599434616}})
 => 120 
ruby-1.8.7-p334 :024 > col.find({:_id => id}).first
 => {"_id"=>BSON::ObjectId4dac55a85fedbd37dd000001, "test"=>-990499976} 
ruby-1.8.7-p334 :025 > col.update({:_id => id}, {:test => 0})
 => 105 
ruby-1.8.7-p334 :028 > col.update({:_id => id}, {"$inc" => {:test => 7599434616.0}})
 => 120 
ruby-1.8.7-p334 :029 > col.find({:_id => id}).first
 => {"_id"=>BSON::ObjectId4dac55a85fedbd37dd000001, "test"=>7599434616.0}