We know that active proliferation prevents the normal functions of tissue cells in vitro.
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For this reason we have found it necessary to modify the present technique of tissue cultivation in order to study more carefully the innate properties of the cells and their relationship one to another. The methods developed by Carrel and his collaborators have provided an excellent means for the study of growth phenomena in general. In the hands of the physiologists, cultures of growing tissues have been mainly used as reagents for the study of the rate of cell proliferation under all possible conditions. But morphologists and embryologists, who expected much from the method, have been rather disappointed. The characteristic structure of the tissue cultivated was very early lost when it was attempted to retain it permanently in vitro. All cells soon came to look alike despite the complexity of the original tissue. In view of these difficulties, many morphologists developed a technique of their own. But in most cases such methods have allowed merely a survival of the cells in various media until death finally occurred.
The method to be reported here is an attempt to create a simple technique for the cultivation of pure strains of tissue cells which will more nearly imitate the conditions found in the adult organism. It is an attempt to discover new properties in the cells, properties which may never be detected under conditions of excessive multiplication.
Into a Carrel flask, of the 3 1/2 cm. D-type, is introduced 0.5 cc. plasma and 1.0 cc. Tyrode solution. Coagulation of the plasma is initiated by the addition of one or 2 drops of embryonic tissue juice. The fragment of tissue is placed in the medium as soon as the tissue juice has been added and before coagulation has occurred. The flask is then closed and placed in the incubator.
