1004 RECORD OF CURRENT RESEARCHES RELATING TO 



species of Punctula, the excessively minute cells of the colony are 

 immobile. They are so closely bound together by a firm cement as 

 not to be easily separated. This is not the case with another species of 

 Ascococcus which the writer met with on the surface of water contain- 

 ing various aquatic plants, where Begcjiatoa was putrefying, and 

 which exhaled a strong odour of ammonia sulphohydrate. Here the 

 cells, also extremely minute, moved with a very rapid oscillating and 

 whirling motion in the interior of the membrane, and having all the 

 appearance of a Brownian movement. Hence this species has been 

 termed Ascococcus vihrans. 



All the social bacteria hitherto described are aerobes, producing 

 an energetic combustion in albuminoid substances on the surfaces of 

 which they are formed, and often, if not always, disengaging a large 

 quantity of ammonia, a phenomenon which Cohn has already described 

 in the case of Ascococcus Billrothii. 



From the observations above described, M. Van Tieghem deduces 

 a confirmation of his view already published that the cell cannot in 

 any sense be regarded as an element. It may, in fact, be split up, a 

 fragment may be separated from it, and this fragment, when placed 

 in favourable conditions, will retain all the properties of the entire 

 cell, and will be able to regenerate it. The plant itself also carries on 

 at every moment this splitting up of its cells into similar and 

 complete parts, often very numerous and minuto. It is indeed on 

 this division that all increase and reproduction depend. The j)roto- 

 plasmic body of a cell is then, in fact, an assemblage of similar 2)arts, 

 each complete in itself, which may be isolated artificially, and which 

 separate from one another naturally by the processes of growth and 

 reproduction, altho^^gh these parts are actually in continuity with one 

 another, and subject to a common law of development. In a large 

 cell there is a great number of these similar parts, and a great 

 number of fragments can be cut oft" from it, equivalent among them- 

 selves and to the entire cell. In a small cell there are fewer such 

 parts. Finally, when the cell is reduced below the size measurable 

 with precision by our existing instruments, the fact that it still divides 

 is clear evidence that it can no longer be regarded as an irreducible 

 element. The analysis of the cell shows, therefore, that it is not, as 

 has generally been stated, the formative morphological element of 

 organisms. 



These observations on social bacteria lead, in another way, by a 

 synthetic path, to the same conclusion. We see, in fact, in them, 

 small cells springing from a primitive cell, and grouping themselves 

 into an intimate association governed by a common law of growth ; 

 this association assuming a definite form and dividing in a certain 

 manner when it has attained a certain size, and then multiplying and 

 maintaining each time its new parts formed in a certain relative 

 position. In one word, this association of similar cells behaves in all 

 respects like a simple cell ; it is, in fact, a compound cell. When 

 crushed, each part is able, like a simple cell, to exist independently, 

 and to regenerate the entire colony. There is, however, one 

 dificrence. This crushing only eft'ects a separation of the cells which 



