1883.] 



MICROSCOPICAL JOURNAL. 



231 



scopists during a year. Tlie theme 

 chosen was not of thrilling interest or 

 novelty, but by making use of the 

 work of others the speaker would 

 endeavor to compress some matter for 

 thought and retlection. He proposed 

 to trace some biological analogies in 

 the animal and vegetable kingdom. 



Among some of the earliest 

 analogies observed between the two 

 kingdoms were those of reproduction, 

 which was noticed in the year 1790 in 

 Hydra, observed to propagate by 

 budding. We know no more of life 

 now than then, but much more of the 

 phenomena of life. Life is the same 

 in animals and plants. Turn to the 

 first germ of either, and we find it a sin- 

 gle cell. It is impossible to distinguish 

 the cell that will develop into a plant 

 from one that will become an animal. 

 A recognition of the identity of all 

 young in appearance, first led to the 

 doctrine of heterogenesis. 



Passing to another series of analo- 

 gies, the speaker referred to the strik- 

 ing resemblances between some of 

 the lower forms of life, which has led 

 to much confusion in classification. 

 When a single cell performs all the 

 functions of life, it is not always pos- 

 sible to know to which kingdom it 

 belongs. The proteus, or amceba, is 

 an animal, but there is a stage in the 

 life-history of certain fungi — the 

 myxomycetes — in which the plant 

 assumes the form of the proteus, 

 and moves about as living jelly with 

 amoeboid motions. This fact has led 

 some authors to regard the myxomy- 

 cetes as of animal nature, and they 

 have been therefore named mycetozoa. 

 This fallacy has been insisted upon in 

 a recent work on the infusoria. It is 

 now known, however, that there are 

 three stages in the life of the plant 

 which gives rise to the amoeboid form, 

 first a condition of active movement, 

 like a swarm-spore, then the amoeboid 

 state, and finally a resting stage. So 

 also in the life-history of Chlamydo- 

 coccus pluvialis there is first a flagel- 

 late stage, then an amoeboid, and 

 finally an encysted, sporiferous condi- 



tion. Dr. Hicks, long ago, observed 

 an amoeboid stage in the cells of 

 Volvos glohaior. He observed the pro- 

 trusion and retraction of the plasma of 

 some of the cells of this plant, and 

 saw them glide along within the 

 family of cells, and bend around some 

 of them. So also the amoeboid con- 

 dition has been observed in Stcphan- 

 osphcera pluvialis, and in C/iara. 

 Even a quarter of a century ago the 

 question was raised by an eminent 

 observer : Does amoeba belong to the 

 animal kingdom ? 



We have sufficient evidence that 

 moving amoeboid bodies do come 

 from Myxomycetes, Chlajnydococcus, 

 Volvox, Sfeplia?iosphcEra, and Chara. 

 Thus we see a close and intimate re- 

 lation between the phenomena of life 

 in animals and vegetals. 



Hackel, in the second volume of 

 his "History of Creation," endeavor- 

 ed to establish an intermediate sub- 

 kingdom in which he classed a great 

 number of forms which seemed to par- 

 take of the characters of both animals 

 and vegetals. These he named the 

 Protista, but among them he placed 

 many forms which are now readily 

 distinguished as animals, such as the 

 rhizopods, and many others now 

 universally regarded as plants, such 

 as the diatoms. This, the speaker 

 said, was a poor method of getting 

 out of a difficulty. Time and patience 

 may reveal the relations between the 

 two kingdoms, and it may be that the 

 Protista will from the starting-point 

 from which they have diverged. 



Every new discovery strengthens 

 the view cf the sexuality of living 

 forms. The zoospores of the alga 

 Botrydium unite, and the product of 

 the union grows into a new plant. 

 Other examples of the same kind were 

 cited by the speaker, in illustration of 

 this part of the subject. 



Metamorphosis, as exemplified, in 

 the butterfly, for instance, is seen in 

 the myxogastric fungi, where we find 

 spores and active zoospores, an 

 amoeboid state, and finally the 

 " imago " or perfect plant. Again 



