FAT TISSUE. 53 



present, however, tissues presenting the above men- 

 tioned morphological characters are usually called 

 mucous tissues, whether the intercellular substance 

 contains mucin or not. Mucous tissue is not found 

 in the healthy human adult, but frequently occurs 

 under pathological conditions. 



TECHNIQUE. 



Subcutaneous Tissue of Embryo. Embryonal connec- 

 tive tissue may be studied in any young mammalian em- 

 bryo, preserved in Miiller's fluid and alcohol. Bits of 

 the subcutaneous tissue are torn off from the abdomi- 

 nal wall, stained double, finely teased, and mounted in 

 glycerin. 



Mucous Tissue from the Umbilical Cord. In the umbi- 

 lical cord of a nearly mature foetus we find typical 

 mucous tissue. A bit of the cord of any mammalian 

 foetus, as the pig, is hardened in Miiller's fluid and alco- 

 hol, then imbedded in celloidin and transverse sections 

 made. These are stained double and mounted in gly- 

 cerin or balsam. The surface of the cord is seen to be 

 covered with laminated epithelium, and the three large 

 blood-vessels are seen to be cut across. The amount of 

 fibrillation present in the intercellular substance depends 

 upon the age of the foetus. 



FAT TISSUE. 



Fat tissue is a modified form of connective tissue, 

 in which the intercellular substance is present in 

 proportionally small amount, and a large part of the 



