124 O. Muhlbock 



Parabiosis 



Another method which apparently has not as yet been 

 much used in gerontological research is that of uniting two 

 animals in parabiosis. Inbred strains are indispensable for 

 this method. If we unite in parabiosis an old animal with a 

 young one, it is possible, e.g., to study the gonadotrophic 

 function of the hypophysis of the old animal, or vice versa 

 the influence of the young hypophysis on the old gonads. 

 The after-care of these parabiotic animals is most essential. 

 In our laboratory the method of putting an older female 

 which has had some litters into the cage of the parabiotic 

 animals as a nurse has appeared to be extremely useful. 



Conclusion 



A survey has been given of the use of inbred strains in 

 experimental gerontology research. It is beyond doubt that 

 inbred strains and their F ± hybrids are indispensable for the 

 investigation of many gerontological problems. 



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