diff --git a/packages/micropolis-engine/src/micropolis.h b/packages/micropolis-engine/src/micropolis.h
index 60141c35..676f84e2 100644
--- a/packages/micropolis-engine/src/micropolis.h
+++ b/packages/micropolis-engine/src/micropolis.h
@@ -968,7 +968,7 @@ class Micropolis {
     /**
      * Callback interface.
      */
-    Callback *callback;
+    Callback *callback = NULL;
 
 
     /**
@@ -1411,8 +1411,8 @@ class Micropolis {
     /**
      * Memory for map array.
      */
-    unsigned short *mapBase;
-    unsigned short *mopBase;
+    unsigned short *mapBase = NULL;
+    unsigned short *mopBase = NULL;
 
 
     void initMapArrays();
diff --git a/packages/micropolis-engine/src/sprite.cpp b/packages/micropolis-engine/src/sprite.cpp
index 5cab2c8f..2eeb884e 100644
--- a/packages/micropolis-engine/src/sprite.cpp
+++ b/packages/micropolis-engine/src/sprite.cpp
@@ -77,6 +77,8 @@
 ////////////////////////////////////////////////////////////////////////
 
 
+#include <new>
+
 #include "micropolis.h"
 #include "text.h"
 
@@ -112,6 +114,8 @@ SimSprite *Micropolis::newSprite(const std::string &name, int type, int x, int y
         freeSprites = sprite->next;
     } else {
         sprite = (SimSprite *)newPtr(sizeof (SimSprite));
+        // newPtr is malloc, so construct the object in place.
+        new (sprite) SimSprite();
     }
 
     sprite->name = name;