1885.] 



MICROSCOPICAL JOURNAL. 



65 



Vertebrates as well as Invertebrates, 

 the phagocytes had the power of in- 

 gesting parasitic bacteria, putrescent 

 blood was injected beneath the skin 

 of the hog, so as to induce septicaemia. 

 After a time the white blood corpus- 

 cles were found to contain both still 

 and motile bacteria, each surrounded 

 by a vacuole. The bacteria were 

 found to be especially abundant in 

 the phagocytes of the spleen, which 

 confirms the statement of patholo- 

 gists that the white blood corpuscles, 

 when they have ingested an insoluble 

 body, are carried into the spleen, in- 

 dicating the prophylactic function 

 of this organ. Further observations 

 made on the larval triton's tail by 

 touching it with nitrate of silver 

 and noting the phenomena of the ensu- 

 ing inflammation have led Metsch- 

 nikoft' to regard the cells of the con- 

 nected tissue as phagocytes, since 

 they act as such during inflamma- 

 tion. 



The observations of Metschnikoff' 

 confirm those of several investigators 

 who assume an active wandering on 

 the part of the white corpuscles them- 

 selves, effected by the protrusion of 

 numerous pseudopodia, similar to 

 those extended by the resting cor- 

 puscles of many Invertebrates ; this 

 observation is not compatible with 

 the current theory of inflammation, 

 which regards imflammation as pri- 

 marily due to a morbid condition 

 of the walls of the blood-vessels. 

 Metschnikoft' believes that the essence 

 of the whole process is a struggle be- 

 tween the phagocytes and the sceptic 

 material whether the latter be a dead 

 or dying cell, or a fungus or other 

 foreign body, thus apparently reduc- 

 ing the whole theory of inflammation, 

 whether caused by an injury to a cer- 

 tain part or due to its invasion by liv- 

 ing organisms as is the case in infec- 

 tious diseases, to a microscopic war 

 between phagocytes on the one hand 

 and foreign bodies on the other, and 

 the result of this must be here as else- 

 where in nature, the survival of the 

 fittest. 



Staining Tissues in Microscopy.*-!. 



BY PROF. DR. HANS GIERKE. 



In 1883 a quarter of a century had 

 past, since the introduction of a 

 method of investigation, that has, 

 more than anything else, assisted to 

 produce the most important results 

 obtained by workers with the micro- 

 scope in modern times. It is of the 

 greatest use in zoological histology, 

 in the medical sciences, and also, if 

 not quite to the same degree, in botany. 



I refer to the treatment of micro- 

 scopical preparations with dyes which 

 differentiate the elements of structure 

 by the different degrees of affinity be- 

 tween the dye and the tissue, whereby 

 portions thereof are stained in various 

 shades or even in different colors. I 

 would offer this essay on the history 

 and processes of this method of study 

 as a memorial of the twenty-fifth an- 

 niversary of its discovery. From im- 

 perfect and modest beginnings it has 

 gradually grown into favor, and dur- 

 ing the last decade with immense 

 rapidity, so that it is perhaps well to 

 arrest the epidemic ambition of those, 

 especially the younger investigators, 

 who search the copious list of dyes 

 for some material that, either pure 

 or modified, they can warmly recom- 

 mend for staining, and thereby be- 

 come an authority. To relate the 

 history of all these methods would 

 make my essay too long, and those 

 which are but repetitions of earlier 

 work will be omitted. With a his- 

 torical review I shall combine some 

 discussion of particular dyes, and the 

 principles governing their applica- 

 tion. Also a list of color-material 

 employed in microscopy, the methods 

 of their preparation and directions 

 for use. I have endeavored in all 

 cases to cite original articles, so that 

 the reader may inform himself there- 

 by. I know well how desirable it is 

 to find the exact manner in which a 

 stain was first applied. Very many 

 hand-books omit to give particulars, 



* From the Zeitschrift fUr wissenscka/tiiche Mi- 

 kroskofiU. Translated for this Jouknal by Prof. 

 ' Wm. H. Seaman, M. D. 



