242 DR. G. THIN. 



course, presupposes a communication between the lumen of 

 the processes of stellate cells and the lumen of the 

 capillary. My information regarding Strieker's views is 

 obtained from Klein's treatise on the omentum.^ The last- 

 named author adopts Strieker's view, with the addition that 

 this excavation of branched cells " goes on both from the 

 already formed vessel, and also isolated in the branched 

 lymph-canalicular cells, which are in direct continuity with 

 the endothelium of the blood-vessels." 



Schafer^ regards the capillaries as being formed in spindle 

 cells, absorption of part of the cell walls where the one over- 

 laps the other being the mechanism by which a continuous 

 tube is formed. Rouget^ regards the projecting process as a 

 development of the protoplasm of the wall of the vessel, 

 which " vacuolates" and then forms a tube continuous with 

 that of the parent vessel. Ranvier^ regards this process as a 

 cellular bud (bourgeon cellulaire), which gradually hollows 

 out as it forms. 



Thus the same appearance is regarded by Strieker and 

 Klein as an enlarging process of a stellate cell ; by Golobew 

 as an outgrowth of a spindle-cell; by Rouget as an outgrowth 

 of the protoplasm of the wall of the vessel; and by Ranvier 

 as a cellular bud. Kolliker used a similar term (sprossen) 

 as applied to the same object, without defining it further. 

 Kolliker was the first to describe this projecting mass as 

 being continuous with the stellate cells of the tissue, in 

 which Strieker and Klein follow him. Golobew, Rouget, 

 and Ranvier, on the other hand, state that they have never 

 seen it become continuous with a stellate cell. 



Ranvier draws a sharp distinction between the growth of 

 a capillary from a pre-existing vessel and the independent 

 development of capillaries in the connective tissue which, 

 after they are fully formed, join the other blood-vessels. 



Klein describes, as we have seen, an independent forma- 

 tion in stellate cells which " vacuolate," and Schafer by the 

 hollowing out of spindle-cells. 



To return to the projecting mass from an already formed 

 capillary. This has been most frequently observed and 

 figured, as seen in the tail of the tadpole. It is easy of ob- 

 servation, and there can be little doubt that the different 

 observers saw exactly the same appearance, as is besides clear 

 enough from their figures. Since the same appearance has 



* 'The ADatomy of the Lymphatic System,' i, p. 61. 



2 .proc. Roy. Soc.,' No. 151, 1874. 



3 ' Arch, de Physiol.,' 1873, p. 603. 



* ' Arch, de Physiol.,' 1874, p. 429. 



