SUMMARY OF CURRENT RESEARCHES 



RELATING TO 



ZOOLOGY AND BOTANY 



(principally invertebrata and cryptogamia), 



MICEOSCOPY, Etc.* 



ZOOLOGY. 



VERTEBRATA. 

 a. Embryology.! 



Mendel's Law and the Heredity of Albinism.}: - - W. E. Castle 

 and G. M. Allen find that complete albinism, without a recorded ex- 

 ception, behaves as a recessive character in heredity. Partial albinism 

 is a mosaic condition, in which the dominant pigment-forming character 

 and the recessive albino character are visible in different parts of the 

 same individual. 



Albinism apparently complete may in reality conceal traces of the 

 pigment-forming character, either in an active or in a latent condition. 

 Albinos that are thus constituted are in reality mosaics of the con- 

 trasted characters, but with the pigment-forming character (ordinarily 

 dominant) occurring in a condition of partial or complete latency. 

 When bred to other albinos they uniformly produce albinos, hence they 

 may for convenience be distinguished as impure recessives. In guinea- 

 pigs and rabbits the impurity of recessive individuals is, in certain cases 

 at least, visible ; in mice it apparently is not. 



Cross-breeding is able to bring into activity latent characters or 

 latent elements of a complex character. This is probably the true ex- 

 planation of many cases of reversion. Conversely, it is able to cause 

 one or another element of a complex character to become latent and to 

 remain so under close breeding. This probably explains how races of 

 black or yellow mice may be obtained by crossing wild grey mice with 

 albinos. 



The Mendelian doctrine of gametic purity is fully substantiated by 



* The Society are not intended to be denoted by the editorial " we," and they 

 do not hold themselves responsible for the views of the authors of the papers noted, 

 nor for any claim to novelty or otherwise made by them. The object of this part of 

 the Journal is to present a summary of the papers as actually published, and to 

 describe and illustrate Instruments, Apparatus, etc., which are either new or have 

 not been previously described in this country. 



t This section includes not only papers relating to Embryology properly so called r 

 but also those dealing with Evolution, Development, Reproduction, and allied subjects. 



t Mark Anniv. Vol.. 190:;, pp. S79-98. 



Feb. loth, 1905 D 



