120 



A n (■ II r () (' |) i I li (■ I i II 111 lins been isolated niid ciilliN'alcd 

 I'or a couple ol" inojilli^ in \ilro. It we dissect Ihroiigli 

 the |)()slerioi' wall of the e.\'e hiiib. it will he (jhscrvcd 

 that a paiM of the retina sticks to the co/'piis vitreum. 

 This i)ai"i can be cullivated wilhout grealei- diiricuUies and 

 is found lo ffrow in cultures in the same typical way as 

 Ihe iris epithelium. 



A m u c o u s-s e c r e t i n 1^ epithelium from the sniall 

 inlesline of the chicken embryo ! have isolated and 

 cultivated. — A small section of the upper i)arl of the 

 intestine of a chicken embryo 15 — 17 days old is jilaced 

 embedded in tlie ordinary culture medium. — Oul from the 

 lumens of the intestine the ei)it helium grows in big sheets 

 and can easily be separated and transferred into a new 

 culture. It will now be interesting to see. if the mucous- 

 secreting epithelium for instance continues to secrete mucous 

 in vitro and interesting to see if ejiithelium with pigment 

 is able l(» i)roduce i)igment in vitr:). 



Innumerable possibilities are opened for the study of 

 the special functions of various tissue cells in vitro under 

 different condition of ex|)ei-iment. It is obvious that the 

 study of the interactions of tlie various tissues will lead 

 to interesting discoveries. 



Quite recently labeling personal communication; has 

 succeded in obtaining a i)ui-e strain of thyroid epithelium. 



CARTILAGE CELLS. 



In the literature on tissue cultivation a few scattered 

 notes can be found about cultivation of cartilage in vitro. 

 In 1910 Carrel and Burrows "J; cultivated conjugal car- 

 tilage among other tissues from adult animals. At that time 

 no attempt was made to isolate pure cells for cultivation. 



In working with the eye of the chicken embryo. T observed 

 in sections from the eye-bulb that it probably would be 

 rather an easy matter to dissect free the thin layer of 

 cartilage in the sclera of the eye. The eye of birds and 



9 

 I 



