Apr. 7. * 9*3 
Temperature Relations of Eleven Species of Rhizopus 23 
gether consistent, seem to indicate that it makes its most rapid growth 
some time after the second day. The growth rate varied with the tem¬ 
perature in most cases. In arrhiziis^ triticij maydis, and artocarpi the 
obvious discrepancies are at the low temperatures, where the curve con¬ 
tinues to rise after the second day. Certain of the fungi— oryzae, arto¬ 
carpi ^ arrhizus, and nigricans —show a rather rapid decline in the rate ot 
growth after the maximum is attained, while others, such as microsporns, 
delemar, and reflexns, show a more gradual decline. In chinensisy so far 
as the data show, there was no reduction in the rate of growth up to the 
time the plates were covered. 
Pig. 16.—Graph showing the increase of growth of Rhizopus microsPofus for consecutive 24-hour periods. 
Fawcett ( 6 ) found that the fungi investigated by him made their great¬ 
est increase in growth during the first two days at the lower temperatures 
and continued to increase at a more gradual rate thereafter. Over a 
small range of the higher temperatures the rate first increased and then 
remained more or less constant till the end of the experiment, while at 
the highest temperatures a continuous decrease was noted from the first 
observational time. In general these results agree wi^ those of the 
writers. Only in oryzae, artocarpiy and tritici at the highest tempera¬ 
tures (38®, 27.5®, and 42° C., respectively) do the graphs show a decrease, 
beginning with the first 24 hours. Nevertheless the fact that the maxi¬ 
mum shifts, as explained above, indicates that such a condition would 
have been found to exist had the proper temperatures—for example, 
temperatures very near the maximumr—been used. 
