486 Rabies. 



of the microscopical examination does not exclude a diagnosis of rabies. 

 In the case of animals which have died from rabies or have been killed 

 at an advanced stage of the disease, the microscopical examination of 

 the brain (cornu ammonis, medulla oblongata, cerebellum) with positive 

 results right after the autopsy, makes an exact diagnosis possible, and 

 in such cases one may also conclude from a negative result that rabies 

 has not been present. In the latter ease, if human beings have been 

 bitten by the animal, the final diagnosis should be made subject to the 

 results of inoculations into animals. 



Negri examined microscopically 75 brains of animals suspected of rabies; 

 in 50 cases the results were positive, and the diagnosis was always confirmed by 

 the biological method, while in 5 out of 72 cases with negative results the 

 inoculation experiments resulted positively. According to Luzzani, up to the year 

 1905, 457 brains of animals had been examined by Italian students for Negri 

 bodies; out of these 297 were proved positive through inoculation, and in only 9 of 

 this number were there no Negri bodies found, while Krajuschkin in 4 out of 34, 

 Nicolas in 7 out of 61, N61is in 2 out of 61, and Bohne in 10 out of 109 cases 

 of established rabies did not succeed in detecting Negri bodies (according to Ball, 

 the number of such non-confirmed findings amounts to about 3.5%). At the Berlin 

 institute for infectious diseases, Lentz on applying the inethod of Mann found 

 Negri bodies 370 times or in 86.4%,, and, on applying his own method, in 52 out 

 of 55 or in 94.5%. Eatz, at Budapest, saw the histological findings confirmed by 

 animal experiments in 258 cases. Hart, at Vienna, found both methods to agree 

 in 498 cases while in 22 cases the histological examination gave negative, the 

 inoculation of animals positive results. 



All students agree that Negri bodies appear exclusively in eases of rabies, 

 and in none of the many cases examined were Negri bodies found without the. 

 inoculation experiments confirming the presence of rabies. 



Techniciue. For the examination the cornu ammonis is most suitable and 

 secondly the cerebellum; but in cats the cerebellum is more satisfactorily examined, 

 because, according to Luzzani, in the cornu ammonis of normal cats formations 

 sometimes appear which in stained preparations are very like Negri bodies in 

 their initial stage. Besides, Standfuss calls attention to the fact that, particularly 

 with nervous distemper in dogs, ganglion cells about to degenerate may contain 

 red colored granules; further, that the karyosome, which may be double has a 

 similar structure and also may be found outside of the nucleus. "Distemper- 

 corpuscles" have also been observed by Lentz, partly in the tissues, partly in 

 highly decomposed ganglion cells; according to his opinion, they originate from 

 the conglomeration of the chromatin substance, and are different from Negri 

 bodies in that they contain no inner granules. 



[At the present time the most suitable method of quickly demonstrating Negri 

 bodies is by Frothingham 's impression preparations, stained according to Van 

 Gieson. A transverse section is cut from the Ammon's horn and placed upon a 

 block of wood near the edge, thus permitting a slide to be pressed evenly upon it. 

 By lifting the slide with a quick motion, an impression of the cut surface of 

 the organ remains on the glass, and, as the histological structure is preserved, an 

 excellent substitute for a microscopic section is obtained. At least four such 

 impressions should be made on one slide, increasing the pressure for each preparation 

 until the tissue becomes quite flat. Before the preparations have dried in the 

 air; fix in methyl alcohol for one half minute, or longer; drain off the alcohol and 

 immediately cover the slide with Van Gieson 's stain heating gently for one-half 

 to one minute; then wash in water, dry with filter paper and examine without a 

 cover glass. The Negri bodies stain a pinkish to purplish red, their inner structure 

 blue. The nerve cells are blue and the red blood corpuscles colorless or yellowish. 

 Van Gieson 's stain consists of 10 cc. distilled water, two drops of a saturated 

 alcoholic solution of rose aniline violet, and one drop of saturated aqueous solution 

 of methylene blue; as modified by Frothingham : 20 cc. of tap water, three ^rops 

 saturated alcoholic solution of basic fuchsin, and one drop saturated aqueous solution 

 of methylene blue. This stain remains effective for about twenty-four hours. Trs.] 



Very pretty pictures, particularly suitable for an exact study of the structure, 

 are given in cover glass preparations and in sections by the staining methods of 

 Mann, Bohne, and Lentz. 



2. Detection of Changes in the Nerve Ganglia. The changes in 

 the ganglia of the peripheral nerves described by van Gehuchten & 



