1881.] 



MICROSCOPICAL JOURNAL. 



49 



Practically speaking, the cooking, 

 salting, and hot smoking which pork 

 in its various forms receives in the 

 United States must be in the vast 

 majority of cases sufficient to kill the 

 trichinae, and prevent infection of 

 the persons consuming the meat. 

 Epidemics like those reported in Ger- 

 many are unknown here, and trichin- 

 iasis in a fatal form is undoubtedly a 

 rare disease. In the vicinity of the 

 great pork-packing establishments 

 near Boston, the " spare-ribs," con- 

 taining the intercostal muscles, are 

 very largely bought and eaten by the 

 people near by ; and trichiniasis 

 among them has not in a single case 

 been reported, so far as I have been 

 able to learn. The cuts being thin 

 and well cooked, any trichinae in 

 them are quite certain to be killed. 

 Even when trichinae are introduced 

 into the intestinal canal, too, they are 

 sometimes expelled by diarrhoea, and 

 the invasion of the system by a small 

 number does no harm. 



Monobromide of Naphthaline 

 and Wax-cells. 



1 send the following extract from a 

 letter received from Herr Weissflog, 

 of Dresden, which will be interesting 

 to many of your readers. I have not 

 used the monobromide of naphtha- 

 line yet myself, but am now preparing 

 some. The slides sent by Herr Weiss- 

 flog show that there is very little dif- 

 ference in regard to the visibility of 

 small transparent diatoms, like A. 

 pellucida, and Rhiz. styliformis, be- 

 tween dry mounts and those in the 

 monobromide. 



The frustules of P. angulatum are, 

 as every one knows, very transparent, 

 sometimes almost invisible in balsam ; 

 but in the monobromide mount, the 

 markings are as readily seen as on the 

 dry frustule, and also the same peculiar 

 color of the dry valve, and the Am- 

 phipleura pellucida is quite as dis- 

 tinct and easily resolvable as in a dry 

 mount. If the use of the monobro- 

 mide will enable us to dispense with 



the preparation of cells for dry 

 mounts, even for diatoms alone, and en- 

 sure their permanancy,it will be a great 

 step in the right direction, and I hope 

 the subject will receive careful and 

 earnest attention. h t c 



* * * You already know that 

 monobromide of naphthaline has been 

 proposed for mounting diatoms in- 

 stead of Canada balsam, and I have 

 for some weeks been experimenting 

 in order to obtain the proper prepa- 

 ration. I send to you to-day three 

 slides, viz.: Amphipleura pellucida, 

 Rhizosolenia styliformis, and Pleurosig- 

 ma angulatum thus prepared. The 

 distinctness of the diatoms as com- 

 pared with the balsam mounts, is very 

 great and is especially noticeable in 

 Rhizosolenia. 



1 have read with much interest 

 your articles on wax-cells ; these, in 

 my opinion, must be thrown aside. I 

 have quite a number of preparations 

 from Eulenstein which are made with 

 wax-cells ; they are completely spoiled, 

 and the covers are loosely attached, 

 and easily removed. 



Herr Lindig of this place, who has 

 had much experience in mounting 

 microscopical preparations, and has 

 for many years sought to find some 

 reliable cement, has arrived at the re- 

 sult that shellac is the best, and he 

 i now uses nothing else. I am de- 

 cidedly of the opinion that the spoil- 

 ing of preparations is partly due to 

 the glass. I have slides of the best 

 plate-glass, and when they are packed 

 away, the outer surface appears after 

 a time, covered with moisture, and 1 

 have noticed a similar effect on a 

 micrometer eye-piece from Ross, of 

 London ; I also agree with Mr. Kitton, 

 that the covering glass can work harm. 

 I have for sometime used glass of 

 Chance Bros., and have often found 

 numerous crystals which appear to 

 come from a kind of sweating, or de- 

 composition of the surface. * * * 

 E. Weissflog. 

 Dresden, January 21st, i88i. 

 o 



