August i6, 1906J 



NATURE 



401 



will prevent the attendance at Section D of some of the 

 chief workers, though two papers on these lines have been 

 promised us, and some aspects of the matlor will, 1 believe, 

 receive attention at the joint meeting which we hold with 

 the botanists, in which several of the prominent foreign 

 workers at Genetics arc expected to take part. 



The subject to which I wish to invite your attention is 

 the life-history of a group of lowly organisms, the 

 Foraminifera, which belong to a division of the animal 

 kingdom standing apart from all others in the simplicity 

 of the organisation of its members, the Protozoa. 



For the last seventy or eighly years the attention of 

 zoologists has been increasingly given to the Protozoa, 

 not only from the interest arising from the particular study 

 of its members, but because, forming as they do a group 

 apart from other animals, and from most plants, they 

 afford a point of view from which to judge of the results 

 on fundamental questions of biology obtained in these more 

 highly developed organisms. 



The problems of the relations between protoplasm and 

 nucleus, the significance of the karyokinetic figures and of 

 chromosomes, the phenomena of fertilisation and the 

 differentiation of sex, are all seen more clearly in the 

 light of the results obtained from the Protozoa. 



Apart from their interest from this wider standpoint the 

 study of the Protozoa has, as I need hardly remind you, 

 received a great impulse of late years from the discovery 

 that, like the bacteria and their allies, the action of which 

 in this respect has been longer recognised, many of them 

 are, when thev gain a footing in the body, the cause of 

 disease in man and other animals. An essential step in 

 counteracting their influence is a knowledge of their life- 

 history and mode of attack. For the proper estimation 

 and interpretation of the facts in the life-history of one 

 organism it is, of course, necessary to be acquainted with 

 its course in allied forms, and in other divisions of the 

 class to which it belongs. 



Whether we approach the matter from the philosophical 

 or utilitarian side an essential step is to obtain as com- 

 pletely as possible the life-histories of species belonging to 

 the main groups of Protozoa, worked out in detail. Certain 

 aspects of the Protozoa, such as the shells of the Foram- 

 inifera, have received a great deal of attention, and we 

 have much accumulated knowledge on particular phases 

 of the life-histories of many forms, but of how few groups 

 can it be said that we know the life-history of any one 

 species completely ! For the last thirty years students of 

 biology have begun their studies with an examination of 

 Amoeba, vet the life-history of the common forms of 

 amoeba, occurring in streams and ditches, still remains, 

 notwithstanding shrewd surmises as to its course — I think 

 Prof. Calkins will permit me to say — unwritten. 



When, therefore, the progress of knowledge of a group 

 reaches a stage in which the main outlines, at least, of the 

 life-history begin to stand forth clearly, it appears to be a 

 matter of importance, not only to the students of that 

 particular group, but, as a standard of comparison, to those 

 of allied groups. 



Such a stage has recently been attained in the study of 

 the Foraminifera, and we are now able to sketch with 

 some certainty the general course of the life-history. I have 

 thought, therefore, that the occasion may not be inoppor- 

 tune for me to put the ascertained facts before you, and 

 endeavour to set them in the light of our knowledge of 

 other forms of Protozoa. 



The zoologist who for the last twelve years has been pre- 

 eminent in the investigation of the Protozoa was Frilz 

 Schaudinn, whose early death occurred last Jime. Be- 

 ginning his work in F. E. Schulze's laboratory at Berlin, 

 his earlier investigations were directed to the Foraminifera, 

 to the knowledge of which he made important contribu- 

 tions; and three years ago he published an account which, 

 as we shall see, completed the main outline of their life- 

 history. His short papers on .■\ctinophrys and various 

 forms of Amceba embody observations of the highest 

 interest. Turning to the investigation of the Sporozoa, he 

 was soon led to devote his attention more especiallv to the 

 organisms which produce disease, and his latest achieve^ 

 ment was to demonstrate the cause of one of the greatest 

 scourges of humanity. 



NO. 1920, VOL. 74] 



Much of his work rests on preliminary accounts of in- 

 vestigations which his splendid activity in research left 

 him no time to publish in detail — though we may hope 

 that, in some cases at least, it may be found possible for 

 the fuller accounts to appear. The papers which he did 

 complete, such as those dealing with the .Alternation of 

 Generations in Coccidia ' and in Trichospha;rium,- are not 

 only contributions of iirst-class merit, but models of re- 

 search and exposition. In all his work he maintained the 

 broad zoological point of view, and his results on the 

 Amccba associated with dysentery are elucidated by those 

 obtained in the study of the Foraminifera. In his insight 

 into the essentials of the problem before him, and his 

 fertility in technical resources, he was, I venture to think, 

 without a rival. 



Having chosen so special a subject, I will endeavour 

 first to set forth briefly the elementary facts of the struc- 

 ture of the Foraminifera, in order that those of my audience 

 who are unfamiliar with them may be able to follow. 



In the hollows between the ridges on a ripple-marked 

 stretch of sand it may often be noticed that the surface 

 Is whiter than elsewhere. On scooping up some of the 

 sand and examining it with a lens it will be found that 

 the whiteness is due in part, no doubt, to fragments of 

 shells of molluscs of one kind or another, but in part to 

 the presence of complete shells of minute size and the most 

 exquisite shapes. Microscopically examined it will be 

 found that in nearly all cases the shells are made up of a 

 number of separate compartments or chambers, communi- 

 cating with one another by one or more narrow passages, 

 and disposed in some regularly symmetrical plan. In some 

 the arrangement is a llat spiral, like that of a watch 

 spring; in others helicoid, like a snail's shell. In some the 

 series of chambers may form a straight or slightly curved 

 line, or they may alternate on either side of a straight 

 axis. There is great variety In the plans on which the 

 shells may be built. They dilTer, too, in texture ; some are 

 transparent, and their walls are perforated by multitudes 

 of minute pores, setting the interior of the chambers in 

 direct communication with the outer world, while in others 

 the walls are semi-opaque, white, and glazed like porce- 

 lain, and such perforations are absent. The shells are com- 

 posed, for the most part, of carbonate of lime contained 

 in an organic " chitinous " matrix, but in many cases 

 grains of sand are included in the walls. 



The planispiral chambered shells present such a close 

 resemblance to the shell of a Nautilus that for a long 

 time, notwithstanding their diminutive size, many of them 

 were actually included In that genus, among the cephalo- 

 pod mollusca. .'\s knowledge advanced the Cephalopoda 

 were divided by D'Orbigny into two groups ; the 

 Siphonifferes, in which, as in Nautilus, the Ammonites and 

 Spirula, the chambers are in connection by a siphon ; and 

 the Foraminif^res, in which they communicate by pores. 



If instead of examining the empty shells left stranded 

 on the shore we take seaweed from shore pools or from 

 shallow water and separate the adherent particles by means 

 of a sieve, similar Foraminiferous shells will be found In 

 the sand which comes through, and these will usually 

 contain the live animal. If glass slides are set in the 

 vessel on the sand, overnight, some of the animals will 

 generally crawl on to them, and they may then be taken 

 out and examined. About these active animals, springing 

 from various points at the periphery of the shell, are multi- 

 tudes of slender threads, forming fan-like or sheaf-like 

 groups, by which the animal is attached to the substratum, 

 and by which it moves. They are composed of a 

 clear hyaline substance — protoplasm — containing scattered 

 granules. If the animal is killed and the shell dissolved 

 by a weak acid, no organs, such as muscles, stomach, 

 brain, and so forth, are found in the interior, but the 

 same granular protoplasm is found to fill the interior of 

 all the chambers. .As in the Protozoa in general, all the 

 elementary functions subserved by the organs of other 

 animals are performed by the undifferentiated protoplasm. 



It was not until 1835 that the simple character of the 



1 V'uf. lib, Generaiionswecksel bet Coccidien. Zoo!. Jahrbucher. Anat. 



BH. 13, IQOO. 



■- Vnt fib. Generaiions-Mechsi-lvon Trkhosphaeritim, Abh. Akad. Berlin. 

 1P99. Anhang. 



