eye-pieces, under the high eye-piece all utterly broke down. The 



sam. Here again the nearly 180" glass gave splendid results, the 

 definition of tin: stria; being perfect even under 1) eye-piece. The 



suit as before. 



These facts seem to justify the claim that the law, as laid down, 

 touching the general usefulness of the wide-angled glasses, is not 

 now correct, having obtained credence at a period when the diffi- 

 culties attending their construction had not been thoroughly mas- 

 tered ; but that such is no longer the case. I feel sure that the 

 advanced workers of this country already accept as true the con- 

 far the greater number of our microscopists still hold to the old 

 faith. — Albert F. Dod, Memphis, Feb., 1875. 



Freezing applied to Histology. — Messrs. Key and Retzius, 

 while admitting the value of freezing as a means of hardening cer- 

 tain tissues for cutting sections, have lately called attention to the 

 false canals which are often formed and which not only disorgan- 

 ize the tissue, but might be mistaken for normal structures. At 



formed may be preserved and demonstrated by hardening the 



Exactly similar appearances may be observed in sections of frozen 

 blood or starchy or gelatinous mixtures. 



Mr. Lawson Tait, of Birmingham, has found sections of tissue, 

 which were cut while hardened by freezing, to be full of air-bub- 

 bles which even the air-pump failed to remove. The contained 

 water had, in freezing, expelled the air it had held in solution, and 

 the bubbles thus produced were so entangled in the tissue as to 

 defy mechanical treatment. They were readily re-dissolved, how- 



reccntly boiled to expel its supply of air. 



Embedding in Elder Pith. — Dr. C. H. Golding Bird, in « 

 paper read before the Medical .Microscopical Society, advocates 

 elder pith as an almost universally preferable medium for embed- 

 ding tis>ues preparatory to cutting sections. For holding in the 



