XL] Sarcina. 117 



observed in the case of other very similar species (see Fig. 15), 

 namely, from a single round initial cell by successive divisions 

 formed in three directions. The packets separate as they 

 grow into daughter-packets, each of which contains the progeny 

 of one of the cells of previous orders of division, and as this pro- 

 cess is repeated the packets multiply. Nothing further is known 

 of the history of the development of Sarcina. 



Sarcina ventriculi is at present known only from the human 

 stomach and intestinal canal. In diseases, especially enlarge- 

 ments, of the stomach, it is often found in incredible quantities. 



/ffl 



a Z c d 



Fig. 14. Fig. 15. 



Yet no causal connection has been ascertained between its 

 occurrence and distinct phenomena of disease, and other con- 

 ditions being the same it may be present in profusion or 

 sparingly, or be absent ; its absence indeed is the rule in much 

 the larger number of stomachs, diseased as well as healthy. The 

 causes of all this are unknown ; nor can we tell whence it finds 

 its way into the stomach. Its occurrence outside the stomach 



Fig. 14. Sarcina ventriculi, Goodsir. Large-celled form just taken from 

 the contents of the stomach of a patient and imbedded in soft gelatine ; a 

 comparatively small and cube-shaped packet. View of one surface only ; but 

 other surfaces project below and to the right beyond the edge of the first. 

 In the surface depicted the cells with double contour-lines are rightly 

 focussed ; those with single contour- lines are not in the right focus but lying 

 at a lower level. Magn. 600 times. 



Fig. 15. Sarcina minuta, de Bary, in gelatine on a microscopic slide. 

 a-d successive states of the same specimen, observed as a double pair of 

 round cells, a about 4, b about 6, c about 9, and d at 10 o'clock in the 

 afternoon. In c the tetrads are still formed of a single layer, in d a division 

 has taken place in each cell in the plane of the paper ; each tetrad de- 

 velopes into an 8-celled cube-shaped packet, /a 32-celled pocket. See 

 note 53. 



