510 SUMMARY OF CURRENT RESEARCHES RELATING TO 



presence of air, if pieces of agar are also present, and may produce as 

 muck or more toxin as in broth in an atmosphere of hydrogen. In 

 broth containing a small quantity of iron filings or ferro-sulphate, 

 bacilli grow well but lose their virulence. By the addition of a little 

 fresh blood-serum to the Na^S0 3 , the toxin production is three to five 

 times increased. 



Investigating Apogamy in Nephrodium.* — Shigeo Yamanouchi 

 raised the apogamous prothallia from ordinary spores, which were sown 

 on sterilised soil consisting of vegetable mould and sand ; these were 

 placed in the greenhouse and kept growing with special care. The 

 cultures, in pots placed on saucers filled with water, were exposed to 

 direct sunlight after the prothallia had developed two or three cells. 

 Excessive evaporation was regulated carefully, and the prothallia kept 

 growing for a long period, exposed to direct sunlight, and at a tempera- 

 ture of from 28-32° C. The rate of growth of these prothallia, as 

 compared with those under normal conditions, was quite slow. Fixation 

 i if the prothallia was made during all stages of development. The 

 killing and fixing of the material, with washing, imbedding, cutting, 

 and staining, was done by the method used in the study of spermato- 

 genesis, oogenesis, and fertilisation. 



Collecting and Examining the Eggs of Rhopalura ophiocomse.f 

 M. Caullery and A. Lavallee remark that Ophiurids infected with 

 Orthonectid parasites are easily recognisable, as they are usually flabby 

 and sterile. The ventral surface is greyish-white, instead of being pale 

 orange ; all parts of the host's body may be invaded. For their study 

 it was necessary that the males and females should be mature, and this 

 point was settled by observing that when ripe, the animals swam about 

 freely when set free in the water by tearing open the host. The hosts, 

 placed in flat glass vessels containing sea-water, and these vessels on the 

 stage of a binocular Microscope, are torn open, and when a sufficient 

 number of both sexes are obtained, the remains of the Ophiurid are 

 removed. The contents of the pans are then poured into a glass vessel 

 containing a thin layer of fresh sea-water. Herein fecundation takes 

 place, and during the next 24 hours, while the eggs are developing, 

 samples are removed from time to time for the purpose of examination 

 in vivo. 



For the study of the fixed material, the procedure was as follows : 

 The animals were picked up with a capillary pipette and transferred to 

 the fixative, usually Bourn's fluid, sometimes acetic-sublimate ; after this, 

 they were frequently washed by decantation, aided by the pipette. This 

 done, each lot was placed in a small tube filled with 80° alcohol, and 

 plugged with cotton-wool. The tube was then immersed in a bottle of 

 80° alcohol. The fecundated females were imbedded in the following 

 manner : A tube 7-8 cm. long, with an internal diameter of about 5 mm., 

 the lower end for a length of 2 cm. being oblong (fig. 134). In this 

 rectangular portion are 2 holes (/fig. 134 A). The end is covered with 



• Bot. Gazette, xlv. (1908) pp. 289-318 (2 pis.). 



t Arch. Zool. Exper. et Gen., viii. (1908) pp. 421-69 (1 pi.). 



