diff --git a/Source/NSBezierPath.m b/Source/NSBezierPath.m
index 4334e00b1..6fb3174b2 100644
--- a/Source/NSBezierPath.m
+++ b/Source/NSBezierPath.m
@@ -572,7 +572,7 @@ typedef struct _PathElement
 //
 - (NSBezierPath *)bezierPathByFlatteningPath
 {
-  NSBezierPath *path = [isa bezierPath];
+  NSBezierPath *path = [object_getClass(self) bezierPath];
   NSBezierPathElement type;
   NSPoint pts[3];
   NSPoint coeff[4];
@@ -631,7 +631,7 @@ typedef struct _PathElement
 
 - (NSBezierPath *) bezierPathByReversingPath
 {
-  NSBezierPath *path = [isa bezierPath];
+  NSBezierPath *path = [object_getClass(self) bezierPath];
   NSBezierPathElement type, last_type;
   NSPoint pts[3];
   NSPoint p, cp1, cp2;
@@ -2073,7 +2073,7 @@ static NSPoint point_on_curve(double t, NSPoint a, NSPoint b, NSPoint c,
   PathElement elem;
   int i, count;
 
-  if (![aPath isKindOfClass: isa])
+  if (![aPath isKindOfClass: object_getClass(self)])
     {
       [super appendBezierPath: aPath];
       return;
diff --git a/Source/NSFont.m b/Source/NSFont.m
index 7fb5d2f22..7242ac1bf 100644
--- a/Source/NSFont.m
+++ b/Source/NSFont.m
@@ -85,7 +85,7 @@ globalFontMap.
 -(BOOL) isEqual: (id)other
 {
   GSFontMapKey *o;
-  if (![other isKindOfClass: isa])
+  if (![other isKindOfClass: object_getClass(self)])
     return NO;
   o = other;
   if (hash != o->hash || screenFont != o->screenFont || role != o->role
@@ -925,7 +925,7 @@ static void setNSFont(NSString *key, NSFont *font)
 {
   if (anObject == self)
     return YES;
-  if ([anObject isKindOfClass: self->isa] == NO)
+  if ([anObject isKindOfClass: object_getClass(self)] == NO)
     return NO;
   if ([[anObject fontName] isEqual: fontName] == NO)
     return NO;
diff --git a/Source/NSParagraphStyle.m b/Source/NSParagraphStyle.m
index 0f82f1c59..406685893 100644
--- a/Source/NSParagraphStyle.m
+++ b/Source/NSParagraphStyle.m
@@ -125,7 +125,7 @@
 
   if (anObject == self)
     return NSOrderedSame;
-  if (anObject == nil || ([anObject isKindOfClass: self->isa] == NO))
+  if (anObject == nil || ([anObject isKindOfClass: object_getClass(self)] == NO))
     return NSOrderedAscending;
   loc = ((NSTextTab*)anObject)->_location;
   if (_location < loc)
@@ -148,7 +148,7 @@
 {
   if (anObject == self)
     return YES;
-  if ([anObject isKindOfClass: self->isa] == NO)
+  if ([anObject isKindOfClass: object_getClass(self)] == NO)
     return NO;
   else if (((NSTextTab*)anObject)->_tabStopType != _tabStopType)
     return NO;