First known description of Ichthyosis hystrix, a group of rare skin disorders in the ichthyosis family of skin disorders characterized by massive hyperkeratosis with an appearance like spiny scales. Digital facsimile from the Royal Society at this link.

Machin’s observations referred to the Lambert family, and were followed through successive generations of the family by Henry Baker in "A supplement to the account of a distempered skin, published in the 424th number of the Philosophical Transactions," Phil. Trans., 1755, 49,  21-24. Digital facsimile of Baker's paper from the Royal Society at this link.