432 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



reference to them would seeui to indicate tbat these forms are not immerous. The suspended 

 matter in the water as it Hows from the tap of tlie laboratory is often so great in amount as to give 

 the water a deep chocolate color. This material under the microscoi)e seems to be of an earthy 

 nature, ami is both amorphons and crystalline, with a few diatoms scattered through it. 



In conclusion, the writer desires to thank Dr. H. S. Warwick, assistant in chendstry in this 

 laboratory, for aid rendered in the course of the chemical work. Thanks are also due to Dr. 

 Amick, of Fifteenth and Indiana avenue; to Mr. Lacky, of Fifth and Lehigh avenue; and to Mr. 

 Seeley, of 2407 Fairmount avenue, from whose respective pharmacies water has been obtained 

 for facilitating the collection of the samples. 



Micrococcus orbiculatus. 



Isolated from the water of the Scliuylkill River. Rare. A rather large nonmotile coccus, 

 occurring in pairs, tetrads, and small clumps. Division takes place in two directions. 



Colonies in (jelatin. — About the fifth day the surface colonies are rounded, elevated, shirdng, 

 whitish disks, about 1 mm. in diameter. After some time they may attain a diameter of 2 to .'J mm. 

 and have a dark yellow color with a pale margin. 



Under a low magnifying power tliey are granular, rather dense and refracting, and have a 

 brownish to warm yellow-brown color. Their outlines are rounded and sharply defined. 



The deep colonies are rounded, I'ather opaque, yellowish, and have sharply defined outlines. 



Gclniin slant. — Rather narrow, brownish yellow, shining, slightly rough stripe witJi scalloped 

 and sharply defined margins. The growth is rather dense and sometimes the margins are paler 

 in color. 



Aciil f/elafin. — Good growth. 



A<i((r slant — Scanty, not widely siireading growth of discrete and continent grayish or 

 yellowish white colonies. 



Bouillon. — Some yellowish, stringy sediment. The reaction is alkaline. 



Potato. — A bright, warm yellow, shining, dense, slightly elevated layer, spreading somewhat 

 irregularly, and with shar])ly defined irregulai outlines. 



Litmus milk. — No coagulation. After a number of weeks may be very slightly pink, and there 

 may be seen a warm yellow-colored sediment at the bottom of the tube. 



Su;iar [jehttin in (h-ep stab. — No growth. 



liusolic acid. — Seems to be slowly decolorized. Reaction is alkaline. 



Inilol -productions. — Negative. Very feeble growth. 



Relation to temperature. — Grows at the temperature of the room and at 3.5° to 3Go 0. 



Micrococcus simplex. 



Isolated from the water of the Schuylkill River. It is probably not uncommon. 



A medium-sized, nonmotile coccus, occurring in pairs, tetrads, and clumps. 



Division seems to take place in two directions. 



Colonies in (jelatin.— Ahont the third day the surface colonies are round, shining, 

 white, semi-translucent disks, about 1 mm. in diameter. Under a low magnifying power 

 they are dense, rather opaque and granular, thinner and sharply defined at their 

 margins, while at their centers there may be a dark nucleus. The deep colonies, under 

 a low power, are dark, brownish, granular, with rounded or slightly irregular sharply 

 defined outlines. They may have a slightly greenish shimmer. In a few days the 

 colonies, now somewhat larger, are seen to be lying in clear liquefixctious, and may be 

 more or less broken up. 



Gelatin sto6.— Li(iuefaction in saucer or cup form (fig. 1). The liquefied gelatin may 



be nearly clear or clouded, and there is an imperfect pellicle of white flocculi on the 



surface, while a whitish granular sediment is at the bottom. There is a fair develop- 



j,jg J ment along the line of inoculation. After the liquefaction has reached the walls of 



the tube it has a level tloor. An alkaline reaction is observed in the liquefied gehitin. 



Acid (jelatin.— Somevfhat less vigorous growth. Liquefied gelatin acquires an alkaline 



reaction. There is little or no growth in tlie line of inoculation. 



v_y 



