THE CELL DOCTRINE. 



63 



We have in the expression of this theory, a prac- 

 tical admission of the spontaneous origin, of animal 

 life, of which Dr. Bennett, in the paper referred to 

 in the Popular Science Review, for January, 1869, 



Fig. 10. 



Fig. 11. 



Fig. 8, Nuclei imbedded in a molecular blastema. Fig. 9, Young fibre-cells 

 formed by the aggregation of molecules around the nuclei of Fig. 8. Fig. 10, 

 Cancer cells, one with a double nucleus. Fig. 11, Histolytic or so-called granule- 

 cells, breaking down from fatty degeneration. 250 diam. linear. (From Ben- 

 nett's Practice.) 



openly declares himself the advocate, while the views 

 are in no way essentially different from those of 

 Schwann. 



Closely allied to this theory is the so-called in- 

 vestment or cluster theory (Umhiillungs-theorie), de- 

 scribed by Virchow on page 53 of Cellular Pathology 

 (Am. Ed. of Chance's Translation): according to 

 which " originally a number of elementary globules 



Fig. 1?, 



Diagram of the Investment (cluster) theory, a. Separate elementary granules. 

 6, Heap of granules (cluster), c, Granule-cell, with membrane and nucleus. 



existed scattered throughout a fluid, but that under 

 certain circumstances they gathered together, not in 

 the form of vesicular membranes, but so as to consti- 

 tute a compact heap, a globe (mass, cluster — Kliimp- 

 chen), and that this globe was the starting-point of 



