340 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1921. 



when there is injected several times into the organism of a species A, 

 crushed tissue of some particular kind coming from a different species 

 B, the serum of A acquires the property of altering or even of dis- 

 solving the antigene B. This property of the serum may, for con- 

 venience of reference, be attributed to an antisubstance, formed by the 

 organism A, which we shall call cytolysin. If now the serum pre- 

 pared from A is injected in an animal B, the cytolysin (no matter 

 whether it is a property or an isolable body) acts by attacking specifi- 

 cally in the living animal the tissues used as antigene (experiment of 

 Bordet, 1898) . Guyer and Smith chose as antigene the crystalline lens 

 of the rabbit and the hen as the source of the antibody. Crystalline 

 lenses of rabbits freshly killed are crushed in a mortar and diluted in 

 the normal salt solution; the liquid is injected at intervals in the 

 peritoneum or a vein of the hens. Several days after the last injection, 

 the serum of one of the hens thus treated is injected in albino doe rab- 

 bits, which have been with young for from 10 to 13 days (a particu- 

 larly important period for the development of crystalline in the fetuses 

 Avhich they contain) ; the injection is repeated at intervals of 2 or 3 

 days during a period of 10 to 14 days. The crystallolysin formed by 

 the hen does not act on the eyes of the adult rabbits, perhaps because it 

 does not reach the crystalline lens, unprovided with any blood vessels ; 

 but it passes through the placentas, and affects more or less strongly 

 the fetuses inclosed in the uterus. Many die; those which survive 

 sometimes have (9 cases out of 61 young) a lens smaller and more or 

 less opaque (giving the eye a bluish color instead of the red of the 

 albinos) or considerable microphthalmia, at times a complete dissolu- 

 tion of the eye. Without any doubt this is due to the specific action of 

 the crystallolysin, for the control rabbits (48) coming from mothers 

 injected either with serum from healthy and normal hens, or with 

 serum from hens prepared with a rabbit tissue other than the crystal- 

 line lens, showed no modification of the visual apparatus. This is no 

 longer a fortuitous coincidence due to a past unnoticed mutation, for 

 in no race of rabbits are there known to be individuals with naturally 

 defective eyes. So far there is nothing absolutely new or surprising 

 for it is already known that cytotoxic serums can pass through the 

 placenta and make an impression on the organs of the fetus. The de- 

 fective eyes of the fetuses constitute a positive acquired character, for 

 if the prepared serum had not been injected in their mothers, their 

 eyes would have been healthy. 



But this acquired character has been shown to be hereditary. It 

 has been transmitted down to the eighth generation without any 

 other treatment than the original injections. The transmission is 

 quite irregular, only one of the eyes being able to be affected, but 

 in the last generations, doubtless because the parents had been taken 



