18jO-91.] amphibia blood studies, 243 



I have now to discuss the nature of these corpuscles and will first of 

 all detail the various views which have been advanced concerning thetn 

 in this respect. 



It is probable that the first observation of these corpuscles was made 

 by von Recklinghausen* in 1866, who described structures, which could 

 have been no other than fusiform cells, in his preparations underg-oing 

 transformation into red cells. He found all the stages of transition between 

 the spindles (fusiform cells) and the elliptical (red) corpuscles, while he saw 

 under favorable conditions in some of the spindles a red shade like that in 

 the ordinary red cells and he regarded these colored spindles as develop- 

 ing red cells. He refers to the fact that in his preparations there are at 

 first small white points, afterwards becoming flat islands (white thrombi ?) 

 consisting of contractile cells which attain enormous sizes and possess 

 contractile processes. In these large cells are developed homogeneous, 

 refracting spheres, sometimes to the number of forty, which may, or may 

 not, be considered as endogenously formed cells. 



Ranvierf is the next to refer to these elements in frog's blood. He 

 describes them as sometimes sharply pointed at both ends or with one 

 end rounded, the other pointed, finely granular and uncolored. He 

 considers them to be free endothelial cells. 



Hayemij: regards these, as well as the platelets of mammalian blood, 

 as haematoblasts. He describes them, as they occur in frog's blood, as 

 smooth, homogeneous, slightly clouded and with a tint less silvery than 

 that of the white corpuscles. They present sometimes a central area 

 lightly shaded, occupying the place of the nucleus, and inside this one or 

 two refracting granules. The nucleus is in every respect like that of the 

 red cell, oval, nucleolated and finely granulated. The disc which is small 

 in volume is flattened, has an elongated, variable form and contains, like 

 the red cells, two distinct constituents, a stroma and a specially organized 

 substance. The stroma is very delicate and, therefore, more difficult to 

 demonstrate than in red cells. The organized matter pervading the 

 stroma differentiates the haematoblasts from the red cell, and it is un- 

 colored or faintly tinted with a small quantity of haemoglobin which it 

 loses easily. This substance is extremely diffusible, and it is endowed 

 with a particular kind of contractility. It is very easily injured, and to 

 this property is due the formation of these corpuscles so readily into 

 granular masses. Hay em subjected frogs to repeated bleedings and 



*Ueber die Erzeugung von rothen Blutkorperchen. Arch, fiir Mikr. Anat., Bd. II., S. 137. 

 tTrait^ technique d'histologie, 1875, P- '9' ^"<i ^9^- 



J Archives de Physiologic, Tome 5, 1878, Tome 6, 1879. Also a later publication : Du Sang 

 €t de ses alterations anatomiques. Paris, 1889, pp. 124-15 1. 



