Of the four layers, all but the third probably were written by a single scribe; a fifth, written by him in ?Leinster circa 1549, is now Adv.MS.72.1.20.

The manuscript is written in the following hands.

1. Text, folios 1-9, 17-21. Hand 1 of Adv.MS.72.1.20. Average to poor in quality. Frequent rising ‘d’. Employs even more contractions than is usual in medical manuscripts. The ink has oxidised in places to an indistinct yellow. Rubricated in red. For a photograph of folio 5 verso, column a (lower half) see CMJ (New Series), volume 6, following page 40.

2. Text, folios 10-16. A more formal variety of hand 1, angular in places and seriffed. Uncoloured save for some crimson in first rubric.

3. Folios 3 verso, 9 recto, 20 verso, 21 verso. Lúcas Ó Maol-tuile. Hand 2 of Adv.MS.72.1.20. Scribbles, mostly illegible.

4. Folio 9, column a. The Reverend John Beaton, hand 3 of Adv.MS.72.1.20.

The contents are as follows.

Folios 1-5 (first layer):

A calendar occupies slightly over half of each page, with an anatomical tract written underneath.

(i) Calendar. Much astronomical information is given, and some saints' days. One month per page; March-April missing due to excision of folio. Ruled in red. Hand 3: ‘Maole’, ‘Edmond’, etc. (folio 3 verso). (Folios 1 recto- 5 verso.)

(ii) On anatomy. Beginning (acephalous) '⁊ tta cuid do r…bh so d' fl[ich]I'. First complete section beginning (folio 2 recto, column a), after lacuna: ‘Osa ultimo anatomia sanatur que sunt in profunnda corporis .i. is arna cnamaibh do niter anatomia’. Ends ‘an cliath na laime ⁊ a .v.’ in section beginning ‘De nervis .i. dona feithibh’. Authorities cited: Lanfranc, Galen, Henricus, Aliabas (folio 2 verso, column b, last line), Avicenna, Guido. Further notes in some lower margins have been erased. (Folios 1 recto-5 verso.)

Of the leaf that has been removed traces of text are visible on the stub.

Folios 6-9 (second layer):

(iii) Continuation from folio 21 verso of commentary on Isaac’s treatise on diets. Ends incomplete ‘⁊ is moille fhagbus an gaile’ in section beginning ‘Pisces fluminum in ac[ti]one et pac[i]one s[un]t contrarii marimis’. Authorities cited: Mithiseus (folio 6 recto, column a), Hippocrates, Galen, Rufus (folio 7 verso, column a, line 8, folio 9 verso, column b, 4th last line), Emisphoridus (folio 7 verso, column b, line 34), Aristotle, Hermeas (folio 9 recto, column b, line 36), Isaac. Hand 3: ‘that…….that’ (folio 9 recto). (Folio 6 recto, column a, line 1.)

On one of the stubs (folio 9 verso, column a) of the two leaves that have been cut, are traces of continuing text and of a marginal note by hand 4.

Folios 10-16 (third layer):

Apparently distinct in origin from the other layers; it is written by hand 2. The scribe makes numerous marginal comments on his text.

(v) St Thomas Aquinas. ‘De operationibus occultis naturae’. Beginning ‘Quoniam in quibusdam naturalibus corporibus quedam acciones naturales aparent .i. osa fhollus gnimartha nad[urdha eig]in’. Ends “Tairnic ann sin tracht[a]d Shancta Tomás de Quino d’ oibr[ighthibh] fol[ach]a na na[duir]e ⁊ Corm[a]c hUa Duinnshleibhi do chuir a nGaeidhilg iat ⁊rl-”. Described by Shaw, in “Medieval medico-philosophical treatises in the Irish language”, page 149. (Folio 10 recto, column a, line 1.)

(vi) Gualterus Burley. ‘De Potentiis animae'. Beginning ‘Ut dicit Philosophus in secundo de Anima. Adon adeir an Feall[samh] annsa .2. l[ebar] don anam’. Ends incomplete “is generalta ni is moidi is aithnidh é” in section beginning ‘Sequitur de potencia’. Described by Shaw, in “Medieval medico-philosophical treatises in the Irish language”, page 153. (Folio 10 verso, column b, line 37.)

Folios 17-21 (fourth layer):

(vii) Commentary on Isaac’s treatise on diets. Beginning ‘Quoniam inprimis coegit antiquos disputare de naturalis cibor[um], adhon as[ed] adeir Ysac annsa l[eb]ar so do rinne se dona dietaibh’. Above this the scribe comments: ‘Ihs Emanuel ⁊ in Dei nomine amen. An tinnsceadal so dop ail lind’. Cf. Trinity College Dublin MS. 1315 (H.2.13), page 190. Lacuna caused by missing leaf from folio 19 verso, colum b, last line, ‘⁊ nach fasduiged’ (in section beginning ‘Ubi vero sine sapor’) to folio 20 recto, column a, line 1 ‘mar aderar innus co teit’; next section beginning ‘Constat ex verbis huius nostri libri’. Authorities cited: Galen, the Sophists, Hippocrates. Continues folio 6 recto, column a, line 1. Hand 3: ‘this...’ (folio 20 verso); illegible (folio 21 verso). (Folio 17 recto, column a, line 1.)

There are also traces of text on the stub, where the fourth leaf has been torn out.