60 CONNECTIVE TISSUES. 



progressing towards the booty. The fibrils are united to one 

 another by an interfibrillar substance, which, at first granular, 

 afterwards becomes homogeneous. In this way the network of 

 branched cells is transformed into fine fibres, arranged in a 

 meshwork ; while the spindle-shaped cells are converted into 

 collections of fibres, running in parallel bundles. A third mode 

 consists in the transformation of isolated spindle or branched 

 cells, which, according to the number of their simple or divided 

 processes, split into a corresponding number of bundles of fi- 

 bres. For the study of the process it is best to employ the 

 umbilical cord, the skin, tendons, or the mucous membrane of 

 the mouth or bladder of young embryos of man or animals. 

 The parts in question should be kept for some time in slieriy- 

 yellow solution of bichromate of potash, after which the tissues 

 may be prepared by teasing in a drop of the solution or in 

 water. It is also desirable, especialty as regards tendons, skin, 

 and mucous membrane of the bladder, to make thin sections, 

 after hardening in solutions of chromic acid or chromates. 

 A splendid object is to be found in the abundant gelatinous 

 substance which covers the internal surface of the gravid 

 uterus of the sow. and extends from thence over the external 

 surface of the membranes of the ovum. If a very small por- 

 tion of this substance is placed in salt solution on a glass 

 slide, and covered without any further preparation, very re- 

 markable forms of large branched or spindle-shaped cells are 

 seen, which consist of evenly granular protoplasm, and con- 

 tain roundish or oblong sharply defined nuclei. The branches 

 are often so large as to stretch over the whole field (Xo. 8 

 Hartnack), and they may be seen to split out at their ends 

 into sheaves of the most delicate fibrils. From the abundant 

 submucous spongy tissue of the gravid uterus of the same 

 animal, instructive preparations maybe obtained (by stripping 

 off fine portions with the curved scissors), which merely re- 

 quire to be spread out with needles in salt solution. If the 

 preparation is to be kept, it may be placed in bichromate of 

 potash and afterwards transferred to glycerin. In the gela- 

 tinous substance previously described as found in the infra- 

 orbital fossa of the rabbit, isolated delicate wavy bundles of 

 connective tissue occur, which, after a shorter or longer course, 

 is seen to be in close relation with processes of slender pale 

 cells which contain round nuclei. 



Hyaline Cartilage. For the study of hyaline cartilage, the 

 episternum of the frog and the thin expansion of the shoulder- 

 girdle of the newt are good objects. If the thin part of either 

 of these is prepared in half per cent, saline solution or in serum, 

 after the perichondrium has been carefully separated with the 

 aid of the sharp forceps, the oblong or spherical cartilage cells 

 are seen embedded in a hyaline or finely granular matrix. The 



