diff --git a/client.go b/client.go
index 7340960f..1674427a 100644
--- a/client.go
+++ b/client.go
@@ -46,7 +46,7 @@ type Client struct {
 // Do performs an asynchronous query. The msg *Msg is the question to ask, the 
 // string addr is the address of the nameserver. The methods returns a channel
 // of *Exchange. If ch is nil, a new channel is allocated and returned. If ch
-// is non nil ch is used and returned.
+// is non nil, ch is used and returned.
 func (c *Client) Do(msg *Msg, addr string, ch chan *Exchange) <-chan *Exchange {
 	switch ch {
 	case nil:
diff --git a/dns.go b/dns.go
index e2d75934..2d1231a1 100644
--- a/dns.go
+++ b/dns.go
@@ -59,10 +59,9 @@
 // server configured on 127.0.0.1 and port 53:
 //
 //      c := new(Client)
-//      in, err := c.Exchange(m1, "127.0.0.1:53")
+//      in, rtt, err := c.Exchange(m1, "127.0.0.1:53")
 //
-// An asynchronous query is also possible, see client.Do or client.DoRtt, when
-// you are interested in the round trip time of the exchange.
+// An asynchronous query is also possible, see client.Do.
 //
 // From a birds eye view a dns message consists out of four sections.
 // The question section: in.Question, the answer section: in.Answer,