^"0. 643] SEROLOGICAL PHENOMENA 



125 



and turn the cell into a specific tissue-cell. Each tissue- 

 cell probably retains all the essential properties of the 

 original fertilized ovum from which it has directly de- 

 scended. In many cases, among lower organisms, at least, 

 we know that somatic cells detached as buds or experimen- 

 tally can through regulation and new growth reconstruct 

 themselves into complete organisms. That a particular 

 cell takes on the characteristics of a specific tissue seems 

 to be determined by the special environment in which the 

 cells happen to be placed in the organism.^ 



Exactly how much chemical difference there is between 

 two unlike tissues or between the cells of a particular 

 tissue and the germ-cells is not known. As far as we 

 have any cytological evidence to the contrary the nuclei, 

 at least, of the tissue-cells are not essentially different 

 from the nuclei of the germ-cells. While the various tis- 

 sues differ very much in appearance, this is mainly the 

 result of the accumulations of intercellular products or 

 of cytoplasmic modifications. And many of the latter 

 may be largely changes in colloidal state rather than 

 fundamental changes in chemical composition. In any 

 event, the new condition is one which has sprung from a 

 cellular chemical constitution similar to that of the orig- 

 inal zygote. And if this is true, would not any internal 

 or external agent which could affect particular proteins 

 of the somatic cells be able also to influence the homol- 

 ogous elements in the germ-cells? 



Inasmuch as I have already twice reported to this Soci- 

 ety on the work* of Dr. Smith and myself with fowl-serum 

 immunized to rabbit-lens by means of which, through 

 injections into pregnant rabbits, we succeeded in obtain- 

 ing defective-eyed young, I shall not again relate the 

 details. The most interesting thing about the experiment 

 was the fact tliat tlie eye-defects were transmissible to 

 subse<pu'iit u<']UMafH«ii>, and inasmuch as the condition 



3C/. CliiM, rnaivi,ln:ility in Organisms also " Origin and Develop- 

 4 Jour. Exp. ZooL, n, 2, 1920. Am. Nat., LV, 1921. 



