39 



To get ii good growth on those substances, it is important 

 to take two things into consideration, namely the contact 

 b e t \\ e e n the tissue and its su|)|)oi't and I li c 

 amount of fluid; Jus! enough fluid that can be held 

 in capillary suction of th(> sup|)orting material, gives tlie 

 best results. It looks, as if the cells ai*e forced to migrate 

 when they ai'e under influence of capillary or surface 

 activity. 



The significance of finding other substances which can 

 be substituted for the fibiMU in the culture medium is 

 evident. Untler conditions of experiment it is often ne- 

 cessary to treat the culture medium in ways which 

 would affect the coagulation of the plasma. Some me- 

 thods of treatment result in the coagulation not taking 

 place, and consefiuenlly no outgrowth occurs. Therefore, 

 we are at present in that resjiect limited in our study of 

 the growth, i)henomena to such conditions only which do 

 not interfere with the coagulating process. A typical example 

 can be brought to notice here. It is impossible to study 

 the rate of growth in culture media with a hydrogen ion 

 concentration over Ph. 5 and below Ph. 8,5 i^o). Only within 

 the limit of Ph. 5 — 8,5 a fairly good coagulation takes 

 place. Therefore it would be important to find another sup- 

 porting substance for the growth of tissue cells when such 

 problems are to be investigated. 



In making several attempts, and especially by using 

 cotton threads as supporting material ^^^\ very interesting 

 observations were made. There is no difficulty in getting 

 a good outgrowth of cells by using a little piece of absor- 

 bent cotton and a drop of embryonic tissue juice. The 

 cells grow out on the cotton threads and often the growth 

 may be so extensive that the oi)en meshes in between the 

 threads are filled up with cells, and by careful examination 

 it is found that the cells grow^ on the liquid film which by 

 surface tension is held in the meshes, (Fig. 1;. The experi- 

 ments mentioned here, suggested that if the cotton threads 



