Eumycetes. — Pflanzenkrankheiten. 667 



minations or lateral branches, on which are produced minute spo- 

 rangia containing usually only one, sometimes two, spores. The 

 genus also resembles Dissophora in possessing specialized structures 

 from which the sporangiophores arise, but is clearly distinguished 

 from the fact, that these structures are intercalary and determinate, 

 as well as by its peculiar sporangia. In general appearance, and 

 in the habit of producing its sporangiophores in a radiate fashion 

 from the segments of repent filaments, it closely resembles certain 

 hyphom^'^cetous forms like Hyalopus or Cephalosporiutn. Two spe- 

 cies are described: H. bisporale found on pig düng at ßurbank, 

 E. Tennessee, on düng of skunk and of field mice at Kiltery 

 Point, Maine and on düng of squirrels at Intervale, New 

 Hampshire. The second species H. decipiens occurred on düng 

 of the curious cave-dwelling Selenodon from Hayti. It is distinguished 

 by its roughened nodding sporangia, smooth spores, which are 

 always solitary in the strain examined, and its slightly larger 

 dimensions. ' Jongmans. 



Bachmann, F. M., The migration of Bacillus amylovoriis in 

 the host tissues. (Phytopathology. III. p. 3—13. 1913.) 



The first evidence of infection by Bacillus amylovorus in the 

 tissues of fruit or shoot is a transparency around the point of inocu- 

 lation, foUowed later by a browning in the same region. From her 

 studies the writer concludes that this transparency is due to the 

 removal of air from the intercellular Spaces, this being replaced by 

 the liquid in which the bacteria live. Doubtless this liquid is cell 

 sap which has been extracted from the cells, thus causing them to 

 lose their turgidity. The cells die, apparently because of a loss of 

 water, although chemical changes in the protoplast may accompany 

 this loss. The substances produced in the metabolism of the organs 

 are, judging from the microscopic evidence, not at all strongly or 

 quickly toxic in their effect on the cells. This is evident because 

 the organisms are found abundantly between cells which to all 

 appearance are entirely normal. The film of liquid in which the 

 bacteria move is not extracted in such amount that it precedes the 

 bacteria to any extent. It seems to the writer that at least all of the 

 first changes in the cells which result from infection may be attri- 

 buted wholly to a loss of water. However, it is possible that the 

 disintegration of the tissues may result in poisonous products which 

 later hasten the death of other cells. 



As to the rate at which the bacteria may migrate, the paper 

 gives no data. Watershoots of apple forty-eight hours after inocu- 

 lation were fixed and when sectioned the organisms were found 

 one-half inch from the point of inoculation. At this time there was 

 only a siight transparency around the wound. The writer repeatedly 

 found that tissues which are to all appearances healthy, contain 

 many bacteria in the intercellular Spaces, 



In the cells of pear fruits there appears to be somewhat less 

 granulär material in the tissues which are diseased. In apple the 

 writer has not observed a diminution in the amount of starch in the 

 cells. The cellulose walls are not digested early, although it seems 

 that digestion in some portions of the walls may have occurred to 

 cause the broken places. If there is a process of cellulose digestion 

 it certainly goes on very slowly and not uniform over all surfaces. 

 It seems possible to explain the broken walls on a purely physical 



