46 Intravenous Injectiom of Mould Spores [March, 



ence of g-erminated spores in the liuigs. This mould is a tropical 

 form growing readily at temperatures above 31° C, and its growth 

 in the rabbits may have cansed death by mechanically interfering 

 with the functions of the organs infected. 



Most species of the miicors will not grow at temperatures over 

 30° C. Among the forms that grow only at relatively low temper- 

 atures, " Mucor V " — a form similar to M. hicmalis, if not identical 

 with this species — gives an especially strong sexual reaction. Its 

 spores are relatively small ( about 8X3-5/^) and can offer little 

 interference to the circulation. No strong toxins, moreover, are 

 developed by this mould such as have been found in the allied form 

 Rhizopus nigricans (i, 2). Altogether, the species seemed espe- 

 cially favorable and has been used in the present investigation. 



The mold was grown, generally on agar, in shallow pie-tins pro- 

 tected with paper covers. Water was poured over the mature cul- 

 ture and filtered through linen which allowed the spores to pass 

 while keeping back fragments of the aerial mycelium which it was 

 feared might block the capillaries. The spore-water was centri- 

 fuged and the resulting compacted mass of spores was mixed with 

 0.9 percent salt Solution and used at once for the injections. 

 Centrifuged spores were dried in a vacuum desiccator and in a few 

 instances were used later when f resh spores were not available. The 

 injections were all made in an ear vein, the usual aseptic precautions 

 being observed. The dose varied from 3 to 4 c.c. The spore- 

 water was always very dark with spores and, although counts were 

 not made each time, the individual injections can be considered to 

 average about 500,000,000 spores. 



Rabbit No. 5, beginning April 2, 191 3. received at intervals of 

 about 4 days, 28 preliminary injections of the spores of the ^ race 

 (3) of "Mucor V." Rabbit No. 55, beginning April 17, similarly 

 received 27 preliminary injections of the $ spores of the same spe- 

 cies. On August 13, five days after the last injection, rabbits Nos. 

 5 and 55 received approximately 800,000,000 spores, respectively, 

 of the (^ and ? races ; and at the same time two control rabbits, 

 Nos. 6 and 66, previously untreated, were similarly injected with 

 like doses of the <S and ? spores, respectively. This made the 29th 

 injection for rabbit No. 5, and the 28th for No. 55. The four 



