468 PEOF. B. C. A. WINDLE ON" TEBATOLOGHCAL EVIDENCE 



recognized as leading up to perodactyly * : — " Two or more digits 

 may be united — (1) by loose folds of skin only (the true webbed 

 condition) t ; (2) by a more intimate connection of tbe skin and 

 deeper soft tissues ; (3) by tlae union or fusion of the bones as 

 well as the soft textures. Besides these forms of union, the 

 digits of one hand or foot, or of both hands and feet, may be 

 all massed together into one lump, so that it may be almost 

 impossible to distinguish the individual fingers or toes," This 

 gradation of defects, the minor ones being of a kind not as- 

 signable to amniotic agencies, is the first point in favour of the 

 blastogenic nature of the defect. A second is the nature of the 

 defect itself. Whoever will take tlie trouble to examine the 

 figures in Porster (Taf. xii. figs. 1-21) will not have much 

 diihculty, I think, in deciding that they are highly unlikely to 

 have been due to amniotic agencies. Many of the absent digits 

 are central, yet these are surely more likely to escape entangle- 

 ment in loops of fibrin than the marginal, which so frequently 

 remain as the sole representatives. 1 may here quote in ecotenso 

 Sturge's remarks to which I have before alluded. Speaking of 

 his case, which he looks upon as one of intra-uterine amputation, 

 he says : — " The congenital deficiency may also be due to (1) a 

 primary inherent abnormal condition of the ovum whereby its 

 healthy development is interfered with in one or more directions ; 

 or (2) a localized morbid condition of one or more parts of the 

 embryo at some time after conception. The former of the two 

 conditions must be invoked in explanation of many cases of 

 monstrosity, in cases where there is congenital hypertrophy of 

 parts, and. it is the most probable explanation of supernumerary 

 parts. There can, therefore, be no reason why it should not 

 produce the opposite condition, viz. congenital atrophy of limbs 

 and congenital absence of portions of limbs. On the other hand, 

 an inflammatory condition capable of throwing out organized 

 lymph in sufBcient quantity to produce intra-uterine amputation 

 is quite as likely, if it attacks that portion of the blastoderm 

 from which a limb is developed, to kill the delicate embryonic 

 cells, or to modify their nutrition so profoundly that their sub- 

 sequent development will be gravely compromised. I think it 

 is worthy of inquiry whether rudimentary fingers have been 

 present in any of those cases where the amputated limb has been 



* Op. cit. p. 46. 



t This may be hereditary. It has been described as passing through four 

 generations. Edinb. Med. Journ. 1858-9, p 501. 



