810 EKPOET — 1893. 



have a clearly defined outline and structure, which difler from those of tissue-cells 

 and their nuclei; they are differently affected by stains. 3. Several observers, 

 and among them one of the present authors (Dr. Cattle *), have pubUshed descrip- 

 tions of what they consider to be a sporing process on the part of the ' parasite.' 



4. They are found most abundantly where the disease is active and spreading ; 

 not where it has died out, and been replaced by scar-like connective tissue. 



5. Drs. Ruffer and Soudakewitch report they have seen the parasite moving and 

 dividing on the warm stage. 



The authors concluded by expressing the opinion that by further observation 

 and experiment, the protozoon of cancer might in time become an established 

 fact. The Paper was illustrated by lantern slides. 



2. On the Wings cf Arch^opteryx and of other Birds. 

 By C. Herbert Hurst. 



The slender hind limbs, the small pelvis, the weak vertebral column made up 

 of amphicoelous vertebrae, and the presence in the fore limb of long, slender, 

 clawed fingers, admirably adapted for climbing in trees, justify the view that 

 Archceopteryx was a quadruped using the free fingers of the fore limb much as 

 the corresponding free fingers of the Pterosauria may have been used, and as the 

 fingers of the ' flying ' squirrels and phalangers, and of Galeopithecus, and as the 

 thumbs of a bat, are undoubtedly used. 



These three slender digits of the wing of Archceopteryx would, however, be 

 useless for such a purpose if the seven large primary quills were attached to them 

 as usually described, and the quills themselves would be useless if so attached ; for 

 the three slender fingers are far too weak, especially at the joints, to withstand the 

 torsional stress to which they would be exposed in flight if the quills were attached 

 to them. A single stroke of the wing would twist those fingers off" at the joints. 

 Such an attachment, indeed, would render both the fingers and the wings useless. 



Comparison of the wing of ArcJueopteryx with the dissected wing of an 

 ordinary bird suggests the position and size and form of bones which would be 

 adequate to support the primary quills of Arehmopteryx, Of these bones Owen 

 figured two metacarpals and a very large carpal bone, and their equivalents have 

 never been exposed in the Berlin specimen. 



In the Berlin specimen, however, the presence of those bones is indicated, and 

 they may even be made out in part in a photograph. The anterior (or preaxial) 

 border of the wing from the carpal angle to the tip of the primary quills forms a 

 bold curve which passes under the three slender fingers. A faint depression 

 behind and parallel to the same fingers indicates roughly the hinder border of the 

 group of bones and ligaments. The slender fingers not only do not contribute to 

 the support of the wing, they do not even lie in the wing at all, but upon its 

 feather-clad surface. The position of the three fingers and the numbers of 

 phalanges (2, 3, and 4 respectively) which they possess show these to be the 

 digits I., II., and III. of the normal pentadactyle limb, and there is hardly room for 

 doubt that two fingers still lie buried in the Berlin slab — fingers which supported 

 the primary quills, which were the equivalents of the two large digits partially 

 exposed in the London specimen, and were also the homologues of the two large 

 digits of an ordinary bird's wing. These were of course IV. and V., and therefore 

 the two large digits of an ordinary bird's wing are IV. and V., and the 'ala 

 spuria ' is all that remains of the other three. 



Well-known arguments against the descent of birds from pterodactyls rest 

 upon the assumption that the two large digits are II. and III., and hence collapse 

 if the interpretation above suggested be accepted. 



3. On the Sensory Canal System of Fishes. By Walter E. Collinge. 



The importance of that system of sensoiy organs in fishes known as the sensory 

 canal, lateral lines, &c., system has not yet been sufficiently estimated, and the 



' British Medical Journal, July 1893. 



