Journal of Applied Microscopy. 



175 



successes have been noted, an equal 

 number of failures were encountered, 

 so no claim is made for picro-car- 

 mine as a "pan" stain. It seems partic- 

 ularly unsuited for tissues that stain 

 with difficulty. 



Ranvier's picro-carmine was used in 

 most of these experiments, but Bizzo- 

 zero's was used with equal success. 

 Mayer's recent formula was used in the 

 histologic laboratory at Cornell last year 

 with results quite as good as those from 

 Ranvier's. 



In summary, then, we find picro-car- 

 mine, in the cases noted, gives, with 

 hematoxylin, a more differential stain 

 than picro-fuchsin and shows the char- 

 acteristic alkaline reaction with hema- 

 toxylin, bringing out the hematoxylin as 

 a beautiful sharp blue, while the acid 

 picro-fuchsin tends to fade it. Two 

 hours is, in general, the best time for 

 picro-carmine. There is no danger of 

 overstaining. 



ALUM-CARMINE. 



During the summer it was my privilege 

 to prepare some slides of liver of guinea- 

 pig to show Anthrax bacilli. The bacilli 

 were readily found, and, at the request 

 of Dr. Moore, pathologist and bacter- 

 iologist of the New York State Veteri- 

 nary College, I attempted to get a con- 

 trast stain, and finally succeeded with 

 alum-carmine. I had tried picro-car- 

 mine without success. In fact I have 

 never been able to secure a good stain 

 with picro-carmine on liver. By experi- 

 ment I found that one hour and fifty 

 minutes with alum-carmine gave the 

 best results. The crystal-violet with 

 which the bacilli were stained, and 

 which is washed out much or entirely by 

 the alcohols and clearer, must be suffi- 

 ciently intense to permit of thorough 

 dehydration and clearing and yet leave 

 a distinct stain. One and one half min- 

 utes will suffice if care is taken not to 

 leave longer than necessary in alcohol. 



By this stain the nuclei and cell body 

 are clearly differentiated and the alum- 

 carmine forms a very good contrast stain 

 with the crystal-violet. The simplicity 

 of the method commends it to us. It is 

 suggested that with methylene blue a 

 still greater contrast may be secured. 

 B. D. Myers, Ph. B. 



Cornell University, Sept. 12, '98. 



Note— I wish to acknowledge my indebt- 

 edness to Dr. Kingsbury for suggestions 

 received during the year, regarding the use 

 of picro-carmine. 



Peroxide of hydrogen will so bleach 

 and clear many insects that the respira- 

 tory system and other organs can be 

 clearly seen. 



Laboratory Methods in Bacteriol- 

 ogy. 



Dr. F. G. Novy, Ann Arbor, Mich. 

 II. — Detection of Pathogenic Organisms. 



The effort was made in the preceding 

 paper to indicate to a beginner the 

 methods of examining bacteria in the 

 living condition and in stained prepara- 

 tions. As in every line of work, practice 

 is necessary in order to obtain the best 

 results. It is well, therefore, to devote 

 extra time to the mastery of the simple 

 methods already described. This pre- 

 liminary practice is essential to the 

 successful application of such methods 

 as aid in the diagnosis of disease. 



The present paper deals with the 

 recognition of the more common disease- 

 producing organisms, by means of the 

 staining reactions. The methods indi- 

 cated are therefore of practical value in 

 diagnosis. The utmost detail is given, 

 because the object in view is to assist and 

 encourage those who have not the direct 

 aid of an instructor. 



GONORRHOEA. 



The cause of this disease is an 

 extremely minute spherical germ or 

 micrococcus, known as the gonococcus. 

 It is found almost invariably in pairs. 

 The two cells in that case are not per- 

 fectly round, but are slightly flattened on 

 the apposed surfaces. The appearance is 

 not unlike that of two biscuits with the 

 flat surfaces brought together. 



The gonococcus is frequently found in 

 groups of ten, twenty, or more pairs. 

 These groups will be found outside of the 

 pus cells. Again, almost invariably some 

 of the pus cells will be found to contain 

 a large number of these minute organ- 

 isms. Anywhere from five to fifty or 

 more pairs of gonococci will be seen 

 inside of some of the pus cells. 



The characteristics to be borne in mind 

 when seeking this organism are: (1) 

 Minute spherical bodies, flattened 

 somewhat when they are brought 

 together in pairs; (2) the tendency to 

 form in groups between the pus cells; (3) 

 the presence of the gonococcus inside of 

 some of the pus cells. 



Detection. — A drop or two of the sus- 

 pected pus is transferred from the 

 urethra to a clean watch glass or to a 

 glass slide. A drop of water should be 

 added to the material and the whole 

 mixed thoroughly with a platinum wire. 

 The water serves to dilute the material, 

 and moreover retards evaporation. It is 

 desirable to examine the pus collected on 

 the first or second day of the disease. 

 In old cases, the secretion may contain 



