diff --git a/src/layers/affine.jl b/src/layers/affine.jl
index c6586cf8..e7cc862c 100644
--- a/src/layers/affine.jl
+++ b/src/layers/affine.jl
@@ -6,16 +6,3 @@ end
 
 Affine(in::Integer, out::Integer; init = initn) =
   Affine(init(in, out), init(1, out))
-
-function back!(m::Affine, Δ, x)
-  W, b = m.W, m.b
-  W.Δx[:] = x' * Δ
-  b.Δx[:] = sum(Δ, 1)
-  Δ * W.x'
-end
-
-function update!(m::Affine, η)
-  update!(m.W, η)
-  update!(m.b, η)
-  m
-end