As in the basic Laracasts.com tutorial (Laracast 5.7 from scratch) I'm trying to use the following methods `public function show(prototypes $prototypes)` parameter to construct a view. However my view is created correctly but `$prototypes` is null.

The route works well(`/prototypes/1/edit`) and I ensured that a `prototype` object with the id 1 exists.
I found some older solution which stated to use something like `(integer $id)` as parameter but this leads to some more code. It should work like this:

Controller:

```php
public function edit(prototypes $prototypes)
{
    //
    return view('prototypes.edit', compact('prototypes'));
}

```

According to *Laracast From Scratch* this should work.

Do you know how I could fix this? 

What mechanism is behind this that the `prototypes.edit` method knows how to use the correct parameter?