[sect. 3]
ut duplicetur: for the classical acc. and infin. after praestare (cf. Cic. Tusc. Disp. 5.29). The same construction is used by Marcellus, Fam. 4.11.2. Similarly the negative form of the dependent clause after praestare is expressed by ne with the subj. in the letters of Cicero's less careful correspondents; cf. Cael. Fam. 8.10.5; D. Brut. Ep. XCVII.1; C. Cass. Fam. 12.13.4.
Cratippo: a celebrated Peripatetic, and young Marcus's principal instructor in philosophy (cf. de Off. 1.1).