TISSUES IN GENERAL. 141 



The re-agents which I used in 1873, with predilection, viz., 

 the nitrate of silver and chloride of gold, are not always 

 reliable, and I admit, had my assertions been based exclusively 

 on specimens treated with these re- agents, they would justly 

 have been considered as nearly worthless. Besides, a certain 

 amount of skill in using those re-agents, and a well-trained eye, 

 are required to see what really can be seen. This is evidently the 

 reason why in Europe, of the many investigators who tried to 

 bring to view the connections of cartilage-corpuscles after 1872, 

 when I first found these connections, only very few have suc- 

 ceeded. Still it was absolutely necessary to demonstrate the 

 presence of such connections, because on cartilage-tissue have 

 mainly rested, for the last forty years, our biological views. 



A. Spina * deserves great credit for the discovery of a new 

 method, by which the connections of cartilage-corpuscles become 

 readily demonstrable even to a relatively untrained eye. This 

 method is as follows : the cartilage, best from the articular ends 

 of bone, for three or four days is placed in alcohol, cut and 

 examined in alcohol. " We are satisfied," Spina says, " that from 

 the cells of the hyaline cartilage project solid offshoots; these, as 

 is easily seen, arise from the bodies of the shriveled cells, pervade 

 the basis-substance, and blend with the offshoots of other cells. 

 The thickness and number of the offshoots greatly vary j the 

 most numerous and most delicate were found in specimens 

 from the superficial portion of articular cartilages of middle- 

 sized frogs," etc., etc. 



From what I have seen, I can heartily recommend this method 

 for the demonstration of the connections, though it is, on account 

 of the shrinkage due to the preservation in alcohol, imperfect. 

 This method brings to view, also, the delicate, mostly rectangu- 

 lar reticulum in the basis-substance of fibrous connective-tissue 

 formations, adjacent to cartilage. 



S. Strieker t recently makes the following statements: 



" The so-called migrating cells in the substantia propria of 

 the cornea, so far as can be ascertained by direct, continuous 

 observation, are neither migrating nor isolated cells. We can 

 easily see, under suitable conditions, that portions of their 

 bodies gradually assume the looks of basis-substance, while new 



* " Ueber die Saftbahnen des hyalinen Knorpels." Sitzungsber. d. Wiener 

 Akad. der Wissensch., 1879. 



t " Mittheilung iiber Zellen und Grundsubstancen." Wiener Mediz. Jahr- 

 biicher, 1880. 



