Hello Charles
The 127.0.0.0/8 address range is called the Internal host loopback address range. Addresses of this form are used to refer to the host itself. If you were to ping any of these addresses on any network device, you should get a response. This is because these addresses refer to the local host. This address range is defined in full in section 3.2.1.3.g of RFC 1122.
In practice, any ping to an IP address of 127.0.0.1 all the way up to 127.255.255.254 will have a response from the local host assuming that the IP protocol stack (the interface itself that is) is up and running. Now theoretically, the 127.0.0.0 and 127.255.255.255 addresses are reserved for network and broadcast respectively, however, in practice, these have no meaning in the context of the local loopback. Indeed I tried pinging 127.0.0.0 on my PC and I got a general failure message. Similarly, I got no response from 127.255.255.255. So these addresses in reality are meaningless in this context.
I hope this has been helpful!
Laz