95 



to describe all variations ol' these inelliods, but only to 

 mention the prototype for I lie technique namely that devel- 

 oped by the Lewis's, l^'or the cultivation of tissues from 

 cold blooded animals, the lecliniciue of Braus -^), U li 1 e n- 

 huth^'J^), Erdmann''"") is beautifully described in their 

 respective papers. 



Lewis and L e w i s use as mentioned before, fluid media 

 for their explantation experiments. The so-called Locke- 

 L e w i s salt solution for cold blooded imimals is the fol- 

 lowing: 



Cultures of tissues from warm blooded animals were 

 usually' cultivated by Lewis and Lewis in Lockes 

 solution: 



Of this solution is taken 80 cc. to 20 cc. chicken broth. 

 The hydrogen ion concentration of the solution were usually 

 pH 6,8 to pH 7,2. 



The technique of Lewi s and Lewis is simply this. 

 On a cover glass is placed a small drop of the Locke- 

 Lewis solution of the above composition and in the drop 

 is placed the small bit of tissue. The cover glass is quickly 

 converted over the hollow-ground slide and is closed with 

 paraffin. In order to get a good contact between the ex- 



