Is there a maximum number of fields in a single matrix? I have a matrix with around 75 fields in it. They are spread over multiple "Block Types". When I create a new field and save the matrix, the new fields aren't being saved. 

Even worse, when I create a new block type with new fields and then drag it up in the order, when I save, Craft is deleting (trimming) the last fields in the matrix - even though they are old (already created) fields.

Does Craft have a limit on the number of fields in a single matrix?

Thanks for your help!
This is because of a combination of settings in your php.ini file:  max_input_vars &amp; post_max_size, not any limitation in Craft CMS. c.f.:

Matrix field input error from within the control panel