Karl Pearson and Adelaide G. Davin 
149 
of the sesamoid itself (FVI) (see our Plate II, Fig. 4). Trew's thesis was re- 
published by Haller, Disputatiommi anatomicaruin selectaruni, Volunien V, 
Gottingen, 1750, p. 475. Figs, v and vi should give the fahella, but the plate is 
missing in the two copies of Haller that we have examined, possibly the plate never 
existed in Haller. The description to Fig. v, C is " C est os sesamoideum insidens 
cavitati condyli exterioris in omnibus femoribus conspicuae." This sesamoid (if only 
a lateral fabella), and the cavity conspicuous in all femora, were something extra- 
ordinary, and Trew seems to have thought so, for he writes as follows : 
Observatio II. Ossieida sesamoidea in femore uc minimo manm diglto. 
Cum aliquando occupatus eraui in ossibus hiimanis a canie sordibu.sque iiiiindandi.s, atque 
accurate in praeparatione artuuni in nunieruui ossiculonnn inquisiverim, cum [irimiK deprcliendi 
numerum sesamoideorum auctum. Priinum mihi antea nondum cognitum se oft'ercbat in feiuoris 
parte inferiori, ubi cum tibia articulatur, in condylo exteriori : ubi in fovea quadam deprehendi 
ossiculum rotundum figura & niagiiitudine Fig. vi. quod instar parvao patellae loco C. Fig. v. 
insidebat in utroque feinore. Putabam tunc teuiporis, id extraordinarium fuis«e ; dum vero illud 
postmodum inquisivi in aliis femoribus, luculcnter semper deprehendi foveam in loco,.cui insidet, 
ita ut deinceps ulterius illius existentiam perserutari excitarcr ; quod & mihi nunquam non in 
tot, quotquot deinceps cadavera inspicere poteram, reperire contigit ; siquidem brevi in quatuor 
illud inveni, atque etiam forsan cuilibet inquirenti patebit. 
It will be observed that Trew does not say that he has ever discovered a mesial 
fabella. But such a big discovery was too much for Trew's anatomical instructor, 
Lawrence Heister. In the first edition of his Compendium an atomic uin, Niirnberg, 
1719, he magnified Trew's lateral fabella into two fahellae, he forgot to mention 
Trew's name and he proclaimed the discovery of two new bones ! One might at 
least have supposed an acquaintance with the text-books of his day. The English 
translation of Heister's work. The Compendium of Anatomy, London, 1752, appears 
to have been made from the earliest edition of Heister, and does not contain the 
long apologetic note of the Niirnberg edition of 1732 (Vol. ii, p. 47) or the Amsterdam 
edition of 1748 (Vol. ll, p. 48). We read on p. 65 : 
There remain now to be considered, the ossa sesamoidea. These are small bones, and are 
most conspicuous in old subjects ; they somewhat resemble the seeds of the sesamum, whence 
they have their name. Their most usual situation is. ..[details of sesamoids of hand and foot] one 
frequently in each external condyle of the os femoris (Tab. i. figs. 2, 3, 4) These are usually 
found in adults, or in elderly people : sometimes though more rarely tliere is one also in the 
internal condyle of the os femoris Ui)on the whole there are very rarely found more than 
sixteen of them often fewer. Those anatomists, therefore err greatly who reckon more than forty 
of them too many, however, have given in to this error. 
All these bones, except those that are found in the condyles of the femur, adhere to the 
tendons of the muscles : those excepted, are connected to the origin of the muscles. Their size 
and shape are various and irregular : they are cartilaginous in young subjects, but they grow hard 
and boncy by age : and it is therefore that they are so much the more easily found in old people. 
They serve as a kind of trochleae to the muscles and increase their power. 
On p. 463 Heister gives an " Explanation of the Figures " (see our Plate II, Fig. 5) : 
Fig. 2. Represents the lower part of the os femoris with two sesamoid b<mes not described 
by other authors. A, The os femoris. B, The internal condyle. C, The external condyle. D, The 
larger of the two new sesamoide bones, situated in a considerable cavity in the external condyle. 
This, however, in some subjects, is much larger than it is represented here. E, The lesser of the 
Biometrika xiii 10 
