394 



Prof. E. W. MacBride. 



[Nov. 7, 



[Note added November 23, 1911. — Since submitting these papers in August 

 several articles by Kurt, Meyer, Muck, and others have appeared upon 

 antigens, other than protein, with their effects both in test-tube and injection 

 experiments. Muck* shows that both tuberculo-fat mixtures and tuberculo- 

 nastin act importantly in both test-tube and living experiments. In contrast 

 to these results Lautf reports that the injection of different tuberculo- 

 products fails in healthy guinea-pigs, rabbits, and goats to produce specific 

 fixation antibodies ; in the horse only were these results obtained.] 



* Brauer's 'Beitrage fur Klin. Tuberc.,' vol. 20, part 3. 

 t ' Zeits. fiir Immunit. Forsch.,' vol. 9, part 2. 



Studies in Heredity, I. — The Effects of Crossing the Sea-urchins 

 Echinus esculentus and Echinocardium cordatum. 

 By Prof. E. W. MacBride, E.R.S., Imperial College of Science and 

 Technology, South Kensington. 



(Received November 7, — Read November 16, 1911.) 



The manner in which parental characters are transmitted to the offspring 

 when different species of Echinoderms are crossed has been the subject of 

 much experimental enquiry and quite contradictory conclusions have been 

 arrived at by different investigators. Thus Vernon (13), who carried out 

 a most extensive series of experiments with the species of the genera 

 Arbacia, Echinus, Strongylocentrotus, Sphaarechinus, and Echinocardium which 

 are available at Naples, came to the conclusion that the condition of the 

 genital glands of the parents (whether imperfectly ripe, fully ripe, or stale) 

 determines in many cases whether or not a hybrid will be formed, and 

 further that though in the majority of cases the hybrid exhibits purely 

 maternal characters, yet it sometimes exhibits paternal characters also, and 

 that this result is also due to the condition of ripeness of the genital glands 

 of its parents. Herbst (5), who also worked at Naples and who used the 

 genera Echinus, Strongylocentrotus, and Sphaerechinus for his experiments, 

 found also that the hybrids in many cases showed the paternal influence, but 

 that the extent to which this influence was exhibited varied with the 

 temperatixre. Doncaster (1), who likewise worked at Naples, also arrived at 

 the conclusion that the greater or less development of paternal characters in 

 the hybrid was due to the temperature. On the other hand, Loeb (7, 8) 

 and his pupil Hagedoorn (4) came to the conclusion that the hybrid exhibited 



