Journal of 



Applied Microscopy. 



Volume I. 



JANUARY, 1898. 



Number 1 



Methods of Study of the Myxamoebae and the Plasmodia 



of the Mycetozoa. 



HOWARD AYERS, Ph. D. 

 Professor of Biology, University of Missouri. 



HABITAT AND COLLECTION OF PLASMODIA 

 AND SPORANGIA. 

 For purposes of experiment and dem- 

 onstration of the morphology and 

 physiology of protoplasm, the Myceto- 

 zoa furnish us with the most satisfac- 

 tory material. In the plasmodial condi- 

 tion the protoplasmic bodies are of mass 

 and extent eufflcient for all the needs of 

 experiment. While it is true that these 

 forms of life have been much used to 

 advance our knowledge of the processes 

 and the material substratum of life, it 

 is equally true that they have not been 

 as much used as they might well have 

 been. The purpose of this paper is to 

 make plain how abundant this material 

 is about us and how it may be used in 

 class demonstration or for original re- 

 search. In all parts of the United States 

 except the desert and snow-covered 

 localities the Mycetozoa are abundantly 

 represented by genera such as Trichia, 

 Arcyria, Hemiarcyria, Stemonitis, Didy- 

 mium, etc., with numerous species, and 

 during the warm spring, summer and 

 fall seasons the plasmodial forms may 

 be found in the moist, quiet localities of 

 forest and woodland, creeping in their 

 fashion over the surfaces of decaying 

 stumps, logs and fallen leaves and oc- 

 casionally on the naked earth where it 

 is full of organic remains. The ripe 

 sporangia are to be found in the same 

 localities. Plasmodia will be found 

 abundant immediately after warm show- 

 ers, especially on sultry, sweltering, 

 summer days when the atmosphere is 

 surcharged with moisture. Newly 

 formed fruiting bodies, or those in the 

 act of forming may be had abundantly 

 on the dry days succeeding such moist 

 periods. The Plasmodia of our common 

 American species are either yellow, 

 brown or reddish brown in color and are 



usually found in a much branched con- 

 dition, spread out upon the decaying 

 wood from which they get their food. 

 They may be easily collected and safe- 

 ly carried to the laboratory or green- 

 house by placing the pieces of wood on 

 which they are spread and which have 

 been cut off from the tree trunk with 

 knife or hatchet, in a botanist's collect- 

 ing case which has been lined with wet 

 filter paper or other good absorbent. 

 Any tin box or glass jar will serve, but 

 a receptacle hung from the shoulder will 

 be found much more convenient than one 

 which must be carried in the hand. On 

 reaching the laboratory the pieces of 

 wood should be placed in dishes under 

 bell jars, with pieces of wet blotting or 

 filter paper to maintain the moist atmos- 

 phere required for their growth. In 

 such a growing chamber they may be 

 kept indefinitely, or until they form their 

 fruiting bodies. Here they may like- 

 wise be fed on any food it is desired to 

 experiment with. The Plasmodia of the 

 Mycetozoa move rapidly when in search 

 of food. This is especially true of the 

 young Plasmodia and ot the myxa- 

 moebae. Hence, when it is desired to 

 keep them under direct microscopic ob- 

 servation, they should be fed previous to 

 any attempt to study them. This may 

 be done by placing them in food solu- 

 tions or feeding them with small parti- 

 cles of animal and plant tissues. After 

 feeding they remain quiet for a time 

 and during this period may be studied 

 to advantage. They may be kept alive 

 indefinitely if supplied with abundance 

 of food and moisture. 



THE GERMINATION OF SPORES. 



The spores of most species of Myce- 

 tozoa germinate at the ordinary spring 

 and summer temperatures of their habi- 



