diff --git a/src/@dseries/merge.m b/src/@dseries/merge.m
index 59ce92e231ae82eee3573dbaa642bef84b359b8f..923fe3afd33fec2ca76b4f0f1614892c374168cc 100644
--- a/src/@dseries/merge.m
+++ b/src/@dseries/merge.m
@@ -82,11 +82,11 @@ elseif firstdate(o) >= firstdate(p)
     Z1 = [NaN(diff, vobs(o));o.data];
     if nobs(q) > nobs(o) + diff
         Z1 = [Z1; NaN(nobs(q)-(nobs(o) + diff), vobs(o))];
-    end;
+    end
     Z2 = p.data;
     if nobs(q) > nobs(p)
         Z2 = [Z2; NaN(nobs(q) - nobs(p), vobs(p))];
-    end;
+    end
     Z = [Z1 Z2];
     q.data = Z(:,IBC);
     q_init = firstdate(p);
@@ -101,7 +101,7 @@ else
     Z2 = o.data;
     if nobs(q) > nobs(o)
         Z2 = [Z2; NaN(nobs(q) - nobs(o), vobs(o))];
-    end;
+    end
     Z = [Z2 Z1];
     q.data = Z(:,IBC);
     q_init = firstdate(o);
diff --git a/src/@dseries/plot.m b/src/@dseries/plot.m
index ed063de456405c2e4821a5165fdbb3504e705f56..f822e77870e799e1354922ddd51fadfba34ba41f 100644
--- a/src/@dseries/plot.m
+++ b/src/@dseries/plot.m
@@ -23,7 +23,6 @@ function h = plot(o, varargin)
 if isequal(nargin,1)
     ndseries = 1;
     nvariables = vobs(o);
-    nobservations = nobs(o);
 else
     if isdseries(varargin{1})
         ndseries = 2;
@@ -41,7 +40,6 @@ else
     else
         ndseries = 1;
         nvariables = vobs(o);
-        nobservations = nobs(o);
     end
 end
 
@@ -50,7 +48,7 @@ switch ndseries
     if isequal(nvariables,1)
         hh = plot(o.data,varargin{:});
     else
-        if length(varargin)
+        if ~isempty(varargin)
             message = sprintf('dseries::plot: dseries object %s has %d>1 variables but you passed additional arguments to the plot function.\n                        These additional arguments won''t ne interpreted. Use the Matlab/Octave set command and the plot\n                        handle instead if you wish to modify the properties of the plotted time series.',inputname(1),nvariables);
             warning(message)
         end