F I G . 5. Two frontal sections through t h e fore-limb b u d s of mole embryos, a t a n early stage of digit development, (a) Polysaccharides
£d
(McManus' technique). Presence of glycogen in t h e three median metapodial precartilages a n d in two carpal elements. Some pre^
cartilaginous masses can be seen a t a more proximal level of t h e carpus, b u t they do n o t contain glycogen yet. (b) Alkaline phosphatase
tj
(v. Kossa-Barger's technique). The enzyme is concentrated in the perichondrial cell layers surrounding the precartilages but the latter
^
have lost all enzymatic activity, ca 2, ca 3—distal precartilages of the carpus; cub.—cubitus precartilage; H.—humerus precartilage; m 2,
3, 4—median metapodial precartilages; m.v.s.—marginal venous sinus; p.c.p.—proximal carpal precartilages; Ra.—radius precartilage.
o
£d
(McManus' technique). Presence of glycogen in t h e three median metapodial precartilages a n d in two carpal elements. Some pre^
cartilaginous masses can be seen a t a more proximal level of t h e carpus, b u t they do n o t contain glycogen yet. (b) Alkaline phosphatase
tj
(v. Kossa-Barger's technique). The enzyme is concentrated in the perichondrial cell layers surrounding the precartilages but the latter
^
have lost all enzymatic activity, ca 2, ca 3—distal precartilages of the carpus; cub.—cubitus precartilage; H.—humerus precartilage; m 2,
3, 4—median metapodial precartilages; m.v.s.—marginal venous sinus; p.c.p.—proximal carpal precartilages; Ra.—radius precartilage.
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