382 SUMMARY OF CUKRENT RESEARCHES RELATING TO 



Reply to Wolff's Article relating to the Spirochczte Question. — Th. Baling * 

 maintains that the spirilla are maceration products, and represent nerve- 

 endings. The author claims that he is supported by Levaditi and 

 Hoffmann, and that Wolff has not made control experiments, and 

 forms his opinion from a neurological point of view. 



Transmission of Siphilis to Rabbits.f — E. Bartarelli succeeded 

 in a number of experiments in producing syphilitic keratitis in rabbits, 

 by injecting syphilitic material into the anterior chamber of the eye. 

 In each case spirocha3t£e were found at a certain distance from the site 

 of the lesion, but not in the lesion itself. Although the symptom com- 

 plications associated with syphilis were not met with, the author considers 

 that etiologically the lesion was of a syphilitic nature. The lesion was 

 successfully transferred from rabbit to rabbit, with the production of a 

 typical spirochaetal keratitis. 



Staining Animal Parasites. J — T.W. Hall stains films of blood, fteces 

 or sediment of secretion for h-2 minutes, with 1 p.c. aqueous methylen- 

 l)lue 100 c.cm., glacial acetic acid 5 c.cm. The film is then contrast- 

 stained with saturated alcoholic-eosin solution, used hot in the usual 

 way. The film is then fixed in potash-alum solution for i-2 minutes, 

 and, after decolorising in alcohol, is mounted in balsam. 



Metallography, etc. 



Crystallisation and Segregation of Steel Ingots. — J. E. Stead § 

 gives the methods he uses fur developing the macrostructure of steel. 

 By etching complete sections of rails, billets, etc., with nitric acid or other 

 suitable reagent, the position of segregated portions resulting from the 

 crystallisation during solidification is made evident. A classification 

 into micro-, minor, blowhole, and axial segregations is given. The 

 author's experiments appear to show that cavities formed in steel by the 

 evolution of gas during solidification are frequently filled up by the 

 still liquid portion ; blowhole segregations thus result. By the addition 

 of aluminium to the molten steel, the formation of blowholes, and thus 

 of blowhole segregation, may be prevented. Sulphur segregates the 

 most, phosphorus and carbon follow in that order ; manganese and 

 silicon do not segregate to any material extent. 



Piping and Segregation in Steel Ingots. — H. M. Howe |1 discusses 

 at some length the causes of piping and segregation, and the methods of 

 restraining these evils. Piping is due chiefly to virtual expansion of the 

 outer walls of the ingot during solidification, and not to a change of 

 volume accompanying the change from the liquid to the solid state. 

 Among the means suggested for lessening piping are casting with the 

 large end up, liquid compression, and devices for retarding solidification 

 such as casting in wide ingots, or in sand moulds. Segregation may be 



* Centralbl. Bakt., Ite Abt. Orig., xliii. (1907) p. 229. 

 t Tom. cit., p. 238. % Brit. Med. Journ., 1907, i. p. 556. 



§ Cleveland lust, of Engineers (1906) 54 pp., 25 figs. Includes the substance 

 of two papers, one read before the British Association, August 1906. 

 II Bull. Amer. Inst. Mining Engineers (1907) pp. 169-274 (36 figs.). 



