lis THE AMERICAN MONTHLY [April, 



urated ferric acetate ; in otlier respects the formula is the same 

 as Loeffler's, except that to the i6 ccm. of the mordant 5-10 

 drops of acetic acid are added. 



When the preparation has been slightly warmed for one 

 minute it is washed in water and then in 20 per cent, acetic acid 

 to give greater clearness. It is again washed in water several 

 times, after which it is warm-stained with anilin-water-fuchsin 

 or anilin-water-gentian -violet. — your. Royal Micr. Soc, Feb.., 

 J 893. 



MEDICAL MICROSCOPY. 



Method for Differentiating between Bacilli of Typhoid 

 Fever and Water Bacteria closely resembling them. — 

 Dr. J. VVeyland examined some drinking water suspected of giv- 

 ing rise to enteric fever, and isolated therefrom a species of bac- 

 terium the morphological and cultivation characteristics of which 

 were not to be certainly distinguished from those of true typhoid 

 bacilli. The negative indol reaction served to increase the sus- 

 picion of their identity. 



The author first set about comparing the vitality of these 

 bacilli with those of real typhoids, but no notable diflerences were 

 shown, and recourse was had to chemistry. As the bouillon 

 cultivation of both kinds had an acid reaction, the amount formed 

 in joccm. of milk serum was first ascertained. For this Pe- 

 truschsky's method was adopted, but phenolphtalein was substi- 

 tuted for litmus as indicator. After having been incubated for three 

 days, it was found that the serum inoculated with the real ty- 

 phoid required 8-9. i ccm. of i-ioo alkali solution to neutralize 

 it, while the pseudo-typhoid took 12. 9-15. 4 ccm. The amount 

 of carbonic acid formed by the two kinds of bacteria was then 

 determined by Pettenkofer's method ; this consists in forcing 

 the carbonic acid formed by the bacteria into tubes filled with 

 baryta water, and estimating the diminution of alkalinity by titra- 

 tion with oxalic acid. 



The only caution to be observed is that the fermentation bulbs 

 must be kept at similar temperatures, as the slightest difterence 

 in heat has an important influence on the production of carbonic 

 acid. This part of the experiment lasted ten days, and the result 

 of it was that the pseudo-typhoid bacilli were found to have 

 produced about five times as much carbonic acid as the true 

 typhoid bacilli. A repetition of the experiment gave a similar 

 result. It was accordingly determined that the water bacteria in 

 question were not typhoid bacilli. — Archiv f. Hygiene., xiv., p. 



374- 



Examining Sputum in Sections. — When examining sputum 

 in cover-glass preparations many of the delicate and fragile cells, 

 says Dr. Gabritschewsky in Deutsh. Med. Wochenschr.., No. 43., 



