418 ANNUAL EEPOBT SMITHSONIAN INSTITUTION, 1912. 



Taken altogether these experiments show that the greater part, 

 if not all, of the bodily organs are able to survive for more or less 

 time after removal from the organism when favorable conditions 

 are furnished. There is no doubt but what the observed times of 

 survival may be considerably prolonged when we have a better 

 knowledge of the serums that are most favorable and the physical 

 and chemical conditions that are most advantageous. 



If we can preserve the organs, we may expect to also keep alive 

 the tissues and cells of wliich they are composed. Biologists have 

 studied these problems, too, and have also obtained in tliis depart- 

 ment some very interesting results. 



The cells which hve naturally isolated in the organism, such as 

 the corpuscles of the blood and spermatozoa, were the first studied. 

 The red corpuscles of the blood of the triton have been preserved ahve 

 in tubes for 8, 10, 12, and even 15 days and have multiplied by 

 division (Jolly, 1903) ; the red corpuscles of the rabbit preserved for 

 12 days in cold storage (Fleig, 1910), then injected into the same 

 animal or into an animal of the same species, produced in the urine 

 no manifestation of globular destruction, which Fleig considers as a 

 proof that the corpuscles were living. The white corpuscles, whose 

 vitaHty is clearly shown by their amoeboid movements, have been 

 preserved in vitro for 12 days (Cardile), 21 days (Recklinghausen), 

 25 days (Ranvier, 1895); those of the triton are still capable of 

 movement after 4 J months of cold storage and those of the frog after 

 1 year (JoUy, 1910) (fig. 4, pi. 1). 



Human spermatozoa have been obsei-ved by Fleig (1909) to be 

 actively motile in semen after being preserved for two or three days 

 at a temperature of 15°. Semen kept in cold storage for eight days 

 and then rewarmed has also shown motile spermatozoa. Ywanoff 

 (1907) was able to preserve in a suitable medium the spermatozoa of 

 a bull at a temperature of 2°, with active movements for 12 days, and 

 at the end of 24 hours obtained artificial fecundations. 



The organized tissues have Hkewise been the object of numerous 

 experiments. The ciHated epithehum of the larynx, trachea, and 

 bronchi of mammals still vibrates 24 hours after death ; Grawitz (1897) 

 observed ciliary movements in the nasal epithehum of man 9 days 

 after its removal during a surgical operation, Wentcher (1894) was 

 able to successfully graft a fragment of human skin 50 hours after 

 its removal. Ljungren (1898) succeeded in doing the same after it 

 had survived for a month. Grawitz (1897) was able to graft a 

 fragment of the cornea of a rabbit removed 12 days previously, 

 Pruss (1900) kept a fragment of cartilage ahve for 30 days. 



Since 1910 experiments on the survival of tissues have multiplied 

 and at the same time more knowledge has been obtained concerning 

 the conditions most favorable to smwival and the microscopical 



