APPENDIX A. 



living substance \ 4. Sarcina, even when obtained from the 

 human stomach, varies considerably, as regards its ultimate 

 pattern or arrangement, as may be seen by reference to 

 Robin's figures ^. 



Some of the forms assumed by these masses alHed to 

 Sarcina are represented in Fig. a. Many other intermediate 

 conditions have, however, been observed; and the careful 

 comparison of one with the other has made me strongly 

 of opinion that Sarcina is only a member of this series of 

 peculiar, not-living formations. 



The next variety of doubtful product met with in the 

 ammonic tartrate solutions is an intricately-tangled spiral- 

 fibre (Fig. 3), which I have previously described^, and which I 

 was at one time disposed to think might be a living organism, 

 I am now, however, more inclined to think that it is a very 

 peculiar formation, which should be placed in the category of 

 Hfeless rather than of living things. Here also, as with 

 Sarcina, though there is good evidence that growth and de- 

 velopment take place, there is no satisfactory evidence of the 

 occurrence of reproduction by the spontaneous separation of 

 portions of its own substance. In default of this, and of all 

 other signs pertaining to living aggregates, it cannot be con- 

 fidently admitted into the same category with them, though 

 it may be just as devoid of all claims to be considered as 

 a crystalline aggregate. It seems, like Sarcina, to be an 

 intermediate product, the existence of which is very far from 

 being incompatible with the truth of the doctrines of evolution, 

 or irreconcileable with our notions as to the nature of livino; 



^ Although I have met with Sarcina and its allies ten or twelve times 

 in the solutions above named, they are by no means to be produced 

 at will. In this respect they are just as uncertain as organisms. On 

 many occasions I have utterly failed to obtain them, although the solu- 

 tions and the conditions were, so far as I could make them, similar to 

 those which had pelded them on previous occasions. 



2 Loc. cit., PI. XII. Fig. I. 3 « Nature,' 1870, No. 36, p. 197. 



