FORMATION OF BLOOD-CELLS. 271 



Reichert. We find that the chyle contains numerous morpho- 

 logical elements, whose supposed significance as embryonic blood- 

 corpuscles, and whose different forms in the course of their deve- 

 lopment, have led physiologists to very different views. H.MUller, 

 who is opposed to the cell-theory of Schleiden and Schwann, thinks 

 that the origin of these bodies from the chyle-plasma may, accord- 

 ing to his observations, be explained somewhat in the following 

 manner: Tn the minutest lacteals there appear minute clots (solid 

 corpuscles without a distinct cell-membrane), which are separated 

 from the chyle, and occur as dense granules, with a viscid matter 

 connecting them together. From these minute clots, the rudiments 

 of the cell- wall arid the nucleus are developed by a certain alteration 

 in the chemical substrata. The nucleus appears most granular in the 

 more recent formations, since it has been formed by the conglome- 

 ration of the insoluble and denser granules, whilst the cell-wall was 

 being condensed into a membranous capsule. Since even at the ter- 

 mination of the thoracic duct we meet with minute clots in which 

 cell-formation is only commencing, it is not improbable that their 

 conversion into true cells that is to say, into colourless blood-cells 

 is effected within the blood itself; in like manner, the first tendency 

 towards the formation of such cells may also take place within the 

 blood from its plasma. Miiller draws attention to the fact, that 

 most of the colourless cells of the blood contain tripartite nuclei, 

 resembling also in this respect pus-corpuscles. We also find that the 

 blood always contains cells with a simple nucleus (like the mucus- 

 corpuscles of healthy mucous membranes) ; and on the other hand, 

 that the chyle contains cells with a multiple nucleus. A slight 

 difference in the chemical constitution of the chyle-plasma on 

 the one side, and of the blood- or exudation-plasma in (suppura- 

 tion) on the other, may perhaps be the cause of a simple nucleus 

 in the former, and of a fissured or multiple nucleus in the latter. 

 Kolliker strongly opposes M tiller's views, and is of opinion that 

 Schwann's theory is strictly applicable to the development of the 

 colourless blood-corpuscles. He found at the commencement of 

 the lacteals, but never in the thoracic duct, nuclei which were either 

 free or surrounded by granules, and young cells with walls which 

 almost touched the nucleus, and were very fragile. He most 

 distinctly maintains the existence of nucleoli. Besides this origin 

 of the lymph-corpuscles in the minutest lacteals, Kolliker also 

 assumes that they are further augmented in the intermediate 

 vessels, although he leaves it undecided whether this increase is 

 effected by endogenous formation or by subdivision. The same 



