1626 Journal of Applied Microscopy 



solved in 100 c. c. distilled water, warmed slightly. The solution was colored to 

 the desired shade with Berlin blue and then five to six grams of potassium iodide 

 is slowly added. Customarily this mass remains liquid and fit for injection at 

 17° C. But should it solidify it is only necessary to add more iodide of potas- 

 sium. A few thymol crystals will make the mixture keep for a month or more if 

 put into a stoppered bottle. A Teichmann's syringe was used, as it had a fine can- 

 nula. Whether the animals were warm or cold blooded they were injected imme- 

 diately after death. The injected objects were then put into five per cent, forma- 

 lin, which fixed the mass most completely, rendering it absolutely proof to chemicals 

 subsequently applied. Hence it is possible to decalcify the material after hard- 

 ening the mass in formalin and not in the least soften or otherwise affect the 

 gelatin. Such material may be left for days in hydrochloric or sulphuric acids 

 without injury. The mass has these advantages : It can be kept ready for use 

 for a long time ; a gelatin block fixed in formol may remain for days uninjured 

 in acids ; the mass penetrates into the smallest vessels and does not diffuse nor 

 fall out of the larger vessels during microscopical sectioning and staining ; it is 

 transparent and allows any process of microscopical technique. No change 

 whatever is noticable in the protoplasm. In a section of lung the minutest ves- 

 sels are injected, the pulmonary artery is filled, and the tissue stained in the 

 usual way. A frontal section of the skull of a triton which has been decalcified, 

 shows the glands with their network of vessels ; on each side the nasal wall, 

 the mucous membrane and rich vascularization. a. m. c. 



Schiiffner. Beitrage zur Kenntniss der Mala- The author considers the study of fresh 

 ria. Deutches Arch, fiirklin. Med. 69:428- malarial blood of little use Owing to 

 449, I tafl., 1899. . ° 



the extremely small size of the parasite 



of typical malaria. Complete fixation is secured by long continued drying in 

 the air. After two to three days the water still shows traces of hemoglo- 

 bin, and after two to three weeks almost none goes into solution. The film 

 is hardened, the albumen has lost its power to swell, and the hemoglobin its solu- 

 bility. Simply drying does not give this air-fixation, as hemoglobin may stay 

 a month unchanged in the drying oven. The change takes place more rapidly 

 in damp air than dry, on damp days than dry, and hence must be a chemical 

 change. Such blood films can be hardened too long and then do not take the 

 usual stains. This can be prevented by drying over sulphurous acid or calcium 

 chloride. It is well after air-fixation for six to thirty-six hours, in the climate of 

 Sumatra, to treat the preparations with Mannaberg's picric-acid solution or alco- 

 hol or sublimate. The author also uses a one per cent, solution of formalin with 

 five to ten per cent, glycerin. Many preparations are lost by drying from the 

 skin (ammonia ?) of the patients. After the air-drying is complete the prepar- 

 ations should be protected from moisture and strong sunlight. The whole pro- 

 cedure is as follows: 1. Draw out the blood drop onto a slide. 2. Air-dry 

 in a place somewhat shielded from sunlight for six to thirty hours. 3. Lay 

 carefully in a dish of fiveper cent, glycerin and formalin, film downwards, keeping 

 the film from contact with the bottom, for five or ten minutes. 4. Lay in spring 

 water for fifteen to sixty seconds. 5. Stain in hematoxylin, according to the 

 strength, for one to ten minutes. 6. Wash out. 7. Dry, mount in Canada bal- 

 sam. 8. Examine first with low powers. In preparations so treated the back- 

 ground is formed of a delicate blue layer of red blood cells, from which the 

 remaining elements of the blood are sharply differentiated. The form-preserva- 

 tion is much better than by Mannaberg's method. a. m. c. 



