1894.] MICROSCOPICAL JOURNAL. 285 



scope to bear upon the tissues of an earthworm ; indeed, it 

 would be hard to find a specimen not infested by some samples 

 of this group of Protozoa. In the invertebrata, however, they 

 do not appear to be fatal to life, or, indeed, to cause any very 

 great inconvenience, and these recent researches of Drs. Ruffer 

 and Walker invest the group with a sinister human interest it 

 has not hitherto possessed. 



BACTERIOLOGY. 



Bacteriology of the Embryo. — Maffucci gives his results 

 of one thousand bacteriological experiments on the chick embryo 

 and of one hundred and fifty on the foetus of the rabbit: he draws 

 the general conclusion that whilst the embryo lives it does not 

 permit the development of pathogenic germs in its tissues save 

 in exceptional circumstances, but may destroy, attenuate, or 

 store up such germs for later develoyment in its extra-ovular 

 life. He states that in some cases a non-pathogenic virus of the 

 adult fowl may be pathogenic as regards its embryo. These con- 

 clusions are founded more upon experiments on the chick than 

 on the fcetal rabbit. The doctor gives the results of his exper- 

 iments on the passage of tubercle bacilli through the placenta 

 from the mother, and on paternal infection of the ovum with 

 tuberculosis. — Tertatologia, April, 1894. 



DIATOMS. 



Staining. — A few years ago I tried some experiments in 

 staining diatoms, hoping to thus secure a more pronounced 

 relief of the delicate markings and a more perfect microscopic 

 resolution of their structure. While in many instances the ef- 

 fects were fine, and the mounts reasonably permanent, I did not 

 push the work to complete success. During the current sum- 

 mer I have employed a great deal of time in carrying forward 

 this work, and with results even more surprising than my former 

 experience warranted me in anticipating. The strength of 

 image of the most delicate forms, and the exquisitely fine bead- 

 ing upon those diatoms which have been heretofore most diffi- 

 cult of resolution, have been wonderfully increased, making the 

 study of their structure a matter of comparative ease. 



The colors which I have used with the greatest success are 



