diff --git a/lib/twitter/core_ext/string.rb b/lib/twitter/core_ext/string.rb
deleted file mode 100644
index 1d7a572b0..000000000
--- a/lib/twitter/core_ext/string.rb
+++ /dev/null
@@ -1,10 +0,0 @@
-class String
-
-  # Converts a snake_case string to CamelCase
-  #
-  # @return [String]
-  def camelize
-    self.gsub(/\/(.?)/){"::#{$1.upcase}"}.gsub(/(?:^|_)(.)/){$1.upcase}
-  end unless method_defined?(:camelize)
-
-end
diff --git a/lib/twitter/factory.rb b/lib/twitter/factory.rb
index 274ceda22..9bbbc20ce 100644
--- a/lib/twitter/factory.rb
+++ b/lib/twitter/factory.rb
@@ -1,5 +1,3 @@
-require 'twitter/core_ext/string'
-
 module Twitter
   class Factory
 
@@ -10,8 +8,10 @@ class Factory
     # @return [Twitter::Action::Favorite, Twitter::Action::Follow, Twitter::Action::ListMemberAdded, Twitter::Action::Mention, Twitter::Action::Reply, Twitter::Action::Retweet]
     def self.fetch_or_new(method, klass, attrs={})
       return unless attrs
-      if type = attrs.delete(method.to_sym)
-        klass.const_get(type.camelize.to_sym).fetch_or_new(attrs)
+      type = attrs.delete(method.to_sym)
+      if type
+        const_name = type.gsub(/\/(.?)/){"::#{$1.upcase}"}.gsub(/(?:^|_)(.)/){$1.upcase}
+        klass.const_get(const_name.to_sym).fetch_or_new(attrs)
       else
         raise ArgumentError, "argument must have :#{method} key"
       end