58 



THE AMEEICAN MONTHLY 



[March, 



6. Hair of Bat. E. Pennock. A 

 test object for moderate powers. 



Box J- came to this circuit Feb. 

 33d to be filled. We have put in a 

 preparation showing male and female 

 fruiting filaments of QLdogo»inm 

 Boscii prepared in 1882. 



Mr. Thomas Christian has contrib- 

 uted a special box, which he very 

 kindly sent to us for examination 

 before starting it on its way through 

 the circuits. It contains six excellent 

 mounts of selected and arranged dia- 

 toms, which are deserving of critical 

 examination. The preparer is very 

 expert in this work. 



NOTES. 



— A new process of double staining has 

 been published by A. Garbini,* particu- 

 larly applicable to thin sections of animal 

 tissues. Two solutions arc used ; the first 

 is composed of anilin blue, soluble in 

 water, i grm., distilled water 100 c.c, ab- 

 solute alcohol 1-2 c.c; the second is com- 

 posed of safranino.5 grm., distilled water 

 100 c.c, absolute alcohol 50 c.c. The 

 sections, either free or attached to the 

 slide, are placed in the anilin blue for 1-4 

 minutes, then immersed in a i per cent, 

 solution of pure ammonia, until the excess 

 of color is removed, and immediately 

 placed in a 0.5 percent, solution of hydro- 

 chloric acid for 5-10 minutes. After wash- 

 ing in water the sections are placed for 4-5 

 minutes in safranin, and finally in abso- 

 lute alcohol. 



— It appears from recent experiments 

 that extreme cold does not kill microbes 

 of putrefaction. Even at a temperature 

 of — • 80° F. their life is not destroyed, and 

 sealed tins and flasks containing putres- 

 cible materials exposed for hours to that 

 low temperature began to decompose 

 when thawed. 



— Mr. W. B. Turner, mjoiirn. R. Micr. 

 Soc, advises the following process for 

 mounting desmids : — 



' When quite fresh gathered, wash and 

 place in a solution of chromic acid, so 

 weak that it requires three days to decol- 

 orize a large desmid. When the color has 

 gone, wash well in at least two waters and 

 stain with anilin. Fix with a little tar- 

 taric or weak nitric acid. Then wash and 



* Di un nuovo nietodo per doppia colorazione. Zool. 

 Anzeiger, ix, (i88S), 26. 



mount in camphorated or carbolized 

 water (about 10 to 90 per cent, disdlled 

 water).' The author states that all deli- 

 cate algeC may be mounted in this way, 

 even the delicate Drapafnaldia. 



— There is strong evidence, which is 

 likely to prove conclusive when the inves- 

 Ugations in progress are completed, that 

 a recent outbreak of scarlet fever in the 

 parish of Marylebone had its origin in 

 milk supplied from a certain dairy. The 

 results are looked for with great interest, as 

 much light may be thrown upon the 

 origin of the disease. 



— In a communication to the Soci^te 

 Beige de Microscopic, M.M. Klement 

 and Renard have presented an interest- 

 ing collection of chemical tests, based 

 upon reactions producing crystalline 

 forms. The full paper will be published 

 in the Annales of the Society, but in the 

 Bulletin a brief resume is given, which 

 includes a list of the principal reactions 

 of elements and the names of the crys- 

 talline compounds obtained by the reac- 

 tions. This list is of considerable value 

 to chemists and persons working in 

 micro-chemistry. 



— Messrs. A. Woodward and B. W. 

 Thomas have studied the foraminifera 

 of the boulder-clay from a well-shaft at 

 Litchfield, Minn. Their results are pub- 

 lished in the report of the geological sur- 

 vey of Minnesota. The foraminifera 

 belong to the cretaceous shales which are 

 found in the clay. Two plates are given, 

 the genera figured being Textiilaria, 

 Spiroplecta, Gaudrvina, Bu/rissina, Glo- 

 bii^n'fina, Lagf/ia, Opcrcu/ina, and Uvig- 

 crina. 



CORRESPONDENCE. 



To THE Editor: — In answer to Mr. 

 Bulloch's first question in the December 

 Journal, I should say the magnifying 

 power would be^,/.^'., the image would be 

 smaller than the object in proportion of i 

 to 9. 



As to the formula of a 2-inch eye-piece, 

 I give the following measurements of 

 one belonging to a large Beck stand 

 which is practically a 2-inch eye-piece : — 

 Focal length of field-lens, small 



central pencil, in inches, . . . 2.460 

 Focal length of eye-lens, central 



pencil, 1-384 



Thickness of field-lens 0.203 



Thickness of eye-lens, .... 0.122 

 Inside distance between lenses, . 1.975 

 Focal length of eye-piece, . . . 1.96 



